But it's kind of like saying that KKK members are secretly ashamed of their black ancestor or that wife beaters are abusive because they wish they were women. Sure, statistically speaking, there are likely a few here and there who are but it doesn't deal with over 99% of the problem.
"Bigotry" is broad concept with different bigotries sometimes having little in common regarding the psychological nature and/or their casual contributors. For one it isn't about wishing you were one of them, but being afraid that your are. Wife beaters are NOT afraid that they are women and whites aren't afraid that they are black, because the outward evidence is rather transparent. However, homosexuality is about unseen desire, and forcible repressed desire, so its plausible for anyone to have such desires, no matter their outward actions. If you are in an environment where being gay has many negative consequences then that possibility will evoke fear in some people and fear is a close associate (experientially and neurologically) to hate and anger.
None of that really applies to bigotry against blacks or women. Also, I think that most racism and sexism is more about ideological ideas that serve a practical social/political agenda rather than the kind of vitriolic deep emotional hate aimed at gays.
Racism and sexism are very idea-based views that more about keeping these groups in their subservient role to preserve social order and reap the benefits of having underlings. IF gays were all second-class servants, I suspect they would still evoke strong hate because it isn't about keeping them down but about their very existence and the threat they pose to one's own identity but also to one's notion of God's perfect creation that reflects his will for how things should be.
Bear in mind that this vitriolic homophobia was even stronger when gays were closeted and few people actually knew any open gays. Homosexuality was little more than an unseen unencountered hypothetical, yet it evoked real vitriolic hate and rage. That indicates something particular about it that is not true of all forms of bigotry (but may be true for anti-atheist bigotry).
Oh, and wife beaters are not all women-haters. They beat for similar reasons people beat their kids. It is not about gender of the victim. Also, actual woman-haters may not fear they are women, but many certainly do fear being viewed as womanly or feminine. Homophobic fear and gender role fear are closely tied.
Usually, when someone acts like an asshole, it's not because of some psychological defence mechanism trying to lash out against something they see in themselves - it's because they're assholes.
I agree that being an asshole isn't usually projected self-loathing for fear that oneself is like them. However, there are many psychological defense mechanisms, so different one's could very well play a role in different assholeness. Also, there are very different kinds of being an asshole, each with different sets of underlying causes. "Because they are an asshole" isn't much of an explanation. Sure, some people are assholes to more often than other people. But are they similarly and asshole to everyone? Are they similarly and asshole to all outgroups? That is rarely true of even the biggest assholes. Thus, more inter-group specific psychological mechanisms are required to account for the to whom, where, and when they are assholes, and also to account for the qualitative nature of their ideas or emotions that trigger the asshole behavior. Fear that one belongs to that group is a partial contributor, and mere fear that one might be thought by others to be part of that group is enough, and neither of those really apply in a similar way to being in a different racial or sex group (mmmm, sex group)
BTW, controlled experiments have shown that gay male porn elicits more penile engorgement in self-labeled hetero males with homophobic attitudes than males without those attitudes. This isn't true of all of them, just significantly more than those without such negative emotions towards gays. IOW, homophobes react to porn more similar to gay men, than do self-labeled straight men without homophobic views.
As an aside, I don't put much stock in the research cited by Juma (nothing personal). Their methods are very weak and rely on the highly dubious "implicit attitudes" method, which is really just a measure of semantic associations that do not indicate why the the words have tiny difference in how strongly they prime each other. Basically, they leave way too many plausible alternative explanations than does how erect your dick gets when you watch men screw each other.
Now, it might be that one of the guys in the crowd that's doing this is gay. Focusing on that, however, is ignoring the problem in the same way as you would if you say that it's actually a pro-gay display because of the one hipster at the school who's wearing flannel ironically. This is happening because the students at this school are dipshits who are expressing their feelings about what dipshits they are, not because they're repressing their feelings about being gay themselves.
Certainly, as a social phenomena there are other maybe more important factors at play, but the fact is that gays are not a random target. IT is quite likely that fear of being viewed as gay and desire to demonstrate that one is not, plays a notable role in heightening the emotional vitriol and desire to participate in social public displays of anti-gay bigotry.
