Men are the perpetrators of the sexism that men experience!

The real perpetrators of the sexism that men experience are, without doubt, other men!

It is men who find gay men and gay marriage, especially of men, to be abhorrent, not women.
It is men who impose upon their own gender stereotypes linked to the pressure to conform, that warp the healthy attitudes of too many young boys, into attempting, often with tragic effects, to fit into those stereotypes. It starts when an older boy ridicules a younger one for "crying" and for "not being a man" no matter what pain the younger boy has just experiences. Even too many parents, fathers and mothers alike, err on the side of a stereotypical form of masculinity in their interactions with young sons. "Don't cry!" "Be a big boy and stop crying!"
And then, in the locker room at the schools, before and after gym classes, there is the predictable, even inevitable, public humiliation by some of the anatomy (specifically the size of the penis) of those young boys who are completely disarmed at the thought that there might even be a competition on such an issue, over which no one has a single ounce of influence. This kind of brutal humiliation is indelibly imprinted on the target's psyche, and decades later, it can be one of the most significant memories of those years. Many "targets" refuse to change their clothes for gym class, risking the punishment of the school rules and the instructor, in order to avoid the embarrassment of these bullying incidents.
And it is bullying, nothing more and nothing less!
And it is boys, often either supported by the teachers, or at best, ignored by the teachers who consider such hazing to be important to grow "strong men"....
There is some validity to some peer criticisms, even in humour, yet these valid occasions are out-numbered by those that cross a line between aggression/teasing and bullying.
If a young boy is not "athletic" he is often ridiculed as a nerd, a fairy, (one of the more frequent epithets!) or a "momma's boy"....especially if that boy displays either talent or interest in the arts. And it is boys primarily who are dishing out the venom. Whether from jealousy, or a feeling of inadequacy (because the stereotypical adolescent is not only not interested in the arts, but often shows no talent for its pursuit) this divide carries over into some demographics in adult life.
The "hockey crowd" (in Canada) is unlikely even to know if there is a good drama, or orchestral concert in the local theatre, let alone attend such an event. Likewise, the families of the dance, music, arts and artistic families are unlikely to dawn the threshold of the local hockey arena, unless there is a special event that includes their interests.
Within the sport of hockey, there is also a divide between those adults who support body-checking and the occasional fight, and those who reject both as unnecessary for the success of the game, at any level.
Cars carry much of the metaphoric value of "muscle" and "girlie" cars...as do movies...and the originators and perpetrators of these classifications are mostly men not women.
Even jobs are often categorized as "masculine" or "feminine" by men who are and have been for some time, in danger of losing their "muscle job" because many of those jobs have evaporated and fled to Asia, India, Bangladesh leaving a few construction jobs for men.
Professions are becoming dominated by women who now outnumber the men in most graduate schools. And of course, as men drop out of the competition in education, they also generate more reasons for not being hired, given the changes in the nature of the economy...from manufacturing to information systems
Hard power continues to dominate the military, as do male stereotypes of "real men" who do not do nuance as George W. Bush described himself.
If there is a conflict between the expectations of women in the workplace, male executives are afraid to find in favour of the male against the complaint of the woman, given the capacity of the women's movement to bind together in support of the woman. Conversely, men rarely, if ever, come to the aid and support of another male in a conflict situation, fearing their own security and reputations, given the dominance of the "women's ethic" and political movement.
If men are neither willing nor able to shed their narrow yet profound grasping of the "stereotypical male model" in favour of a multiple series of models of masculinity, then men will continue to slide down a scale that too often leads to drug and/or alcohol abuse, violence either of the street or the domestic variety, and even suicide.
Just this week, we learned that every day, in the U.S. there are 22 suicides among war veterans, and without having the numbers of male to female victims, there is clearly a male penchant and preference for declaring war in the first place, no matter what the situation. And that preference currently illustrates one of the main divides between the U.S. President who prefers to move cautiously in such complex emergencies as Syria, and Republican "hawks" like Senators Lindsay Graham and John McCain, both of whom reject gun control legislation, and advocate more military intervention by the U.S. to demonstrate "strength" in Syria, in order to establish the U.S. supremacy in the aftermath of the Syrian civil war....another manifestation of the need for "masculinities of power and control" achieved through the power of the gun, the missile, the jet fighter and the aircraft carriers.
When schools and school systems fall into the trap of hiring female instructors and leaders almost exclusively, the fifty percent of the student population, the boys, will be warped into conformity with that female culture...and only male father, uncles, mentors and interested citizens can bring this imbalance to public attention.
Women who advocate for the job opportunities that women can effectively fill will not abandon their sisters in favour of a balanced hiring policy and practice.
However, just this year, the Toronto District School Board has announced that, in its hiring for the fall term, the top quality sought in prospective hires for the classroom is MALE!
That is a small sign that someone has noticed the disparity that has existed in too many school boards for too long, disadvantaging the male students who comprise half of the student bodies of all schools, except, of course those of exclusively female enrolments.
And then there is this piece from the recent edition of The Atlantic:

When Men Experience Sexism
There are some practices and policies that are unfair to men. But this fact should unite men with feminists, not drive them apart.
By Noah Berlatsky, The Atlantic, May 29, 2013
David Benatar, in his 2012 monograph The Second Sexism discusses a whole range of other ways in which men as men are disadvantaged. Men, for example, receive custody of children in only about 10 percent of divorce cases in the United States. Men also, as Benatar writes, are subject to "a long history of social and legal pressure...to fight in war" —pressures which women do not generally experience in the same way. Along the same lines, physical violence against men is often minimized or seen as normal. Benatar refers to the history of corporal punishment, which has much more often been inflicted on boys than girls. Society's scandalous tolerance of rape in prison seems like it is also related to a general indifference to, or even amusement at, sexual violence committed against men.
Perhaps most hideously, men through history have been subject to genocidal, or gendercidal, violence targeted at them specifically because they are men. Writers like Susan Brownmiller have over the last decades helped to show how mass rape and sexual violence against women are often a deliberate part of genocide; similarly, there has been increasing awareness in recent years of the gendercidal results of sex-selective abortion and infanticide in places like India and China. But the way gendercide can be directed against men is much less discussed. One of the worst recent examples of this was in the Balkans war, where, according to genocide researcher Adam Jones, " All of the largest atrocities... target[ed] males almost exclusively, and for the most part "battle-age" males. " Similarly, in Rwanda according to Judy El-Bushra (as quoted by Jones):
it was principally the men of the targeted populations who lost their lives or fled to other countries in fear. ... This targeting of men for slaughter was not confined to adults: boys were similarly decimated, raising the possibility that the demographic imbalance will continue for generations. Large numbers of women also lost their lives; however, mutilation and rape were the principal strategies used against women, and these did not necessarily result in death.
Many of these examples—particularly the points about custody inequities and conscription—are popular with men's rights activists. MRAs tend to deploy the arguments as evidence that men are oppressed by women and, especially, by feminists. Yet, what's striking about instances of sexism against men is how often the perpetrators are not women but other men. The gendercides in Serbia and Rwanda were committed against men, not by feminists, but by other men. Prison rape is, again, overwhelmingly committed by men against other men—with (often male) prison officials sitting by and shrugging. Conscription in the U.S. was implemented overwhelmingly by male civilian politicians and military authorities, not by women.
Even in cases where women clearly benefit from sexism, it's generally not the case that women, as a class, are the ones doing the discriminating. Neither alimony nor custody discussions are central to current feminist theory or current feminist pop cultural discussions. There is no ideological feminist commitment to either of these discussions in the way there is to, say, abortion rights, or workplace equity. On the contrary, the alimony and custody inequities we have at the moment seem mostly based, not on progressive feminism, but rather on the reactionary image of female domesticity that feminism has spent most of the last 60-odd years fighting against.
When men suffer from sexism, then, they do so in much the same way women do. That is, they suffer not because women rule the world and are targeting men, nor because feminism has somehow triumphed and brainwashed all of our elected officials (most of them still men) into ideological misandry. Rather, men suffer because of the same gender role stereotypes that hurt and restrict women—though men, being of a different gender, fall afoul of those stereotypes in different ways. Women are supposed to be passive and domestic and sexual—so their employment options and autonomy are restricted and they are fetishized and targeted for sexual assault and exploitation. Men are supposed to be active and violent—so their claims to domestic rights are denigrated and violence directed against them is shrugged off as natural or non-notable.
"For me," Heather McRobie wrote in an excellent 2008 article about genercide, "feminism has always been about how rigid gender roles harm everyone, albeit primarily women." Talking about sexism against men is often seen—by MRAs and feminists alike—as an attack on feminism. But it shouldn't be. Rather, recognizing how, say, stereotypical ideas about domesticity hurt men in custody disputes as well as women in the job market should be a spur to creating alliances, not fissures. Women have been fighting against sexism for a long time. If men can learn from them, it will be to everyone's benefit.