Gaydar is for real:
Nicholas Rule and Nalini Ambady from Tufts University perused online dating sites and carefully selected 45 straight male faces and 45 gay male faces. All of these photos were matched for orientation (only faces shown looking forward were used) and facial alterations (none of the images contained jewelry, glasses or facial hair). To control for context, the faces were also cut and pasted onto a white background for the study. These 90 faces were then shown to 90 participants in random order, who were asked simply to judge the target's "probable sexual orientation" (gay or straight) by pressing a button. Surprisingly, all participants (both men and women) scored above chance on this gaydar task, correctly identifying the gay faces. Even more surprisingly, accuracy rate was just as good when the images were exposed at a rapid rate of only 50 milliseconds, which offered participants no opportunity to consciously process the photo....
Furthermore, in an even more rigorously controlled series of experiments published in the Journal of Personality and Social Psychology, Rule and his colleagues replicated their discovery that people are able to accurately guess male sexual orientation. This time, the researchers demonstrated that perceivers were able to do this even when they were shown only individual features of the target's face. For example, when shown only the eye region ("without brows and cropped to the outer canthi so that not even "crow's-feet" were visible"), perceivers were amazingly still able to accurately identify a man as being gay.
You know, people had gaydar back in the bad old days—back before gay people started coming out and living openly—but Marcus Bachmann would've gotten a pass. He would've gotten multiple passes: a pass for the way he looks, for the way he speaks, the way walks, the way he dances. Being a homosexual used to be considered so vile, disgusting, and immoral—so criminal—that a man like Marcus Bachmann had to be given the benefit of every doubt. Being gay was literally the worst thing you could think about a person. So straight people went out of their way to avoid thinking it. Even when evidence of a man's gayness was on conspicuous display, straight people would refuse to see it. Which explains why millions of blue-haired old ladies went to their graves convinced that Liberace was straight.
Times have changed.
Straight people haven't just gotten used to gay people—to openly gay people—they've come to the realization that they prefer openly gay people to lying closet cases. They would rather have a beer with an honest Cam than a glass of champagne with a lying Liberace. And that's why Marcus Bachmann is being ridiculed: it's not because he's perceived to gay—it's not because he pings on everyone's gaydar save Michele's—it's because he's perceived to be dishonest. He appears to be a lying closet case, a lying closet case who's made convincing other gay people to join him in the closet his life's work. And straight people don't like being lied to.