People make all kinds of judgments based on appearances. They see a man wearing a dress and they think he's gay. What does liking to wear pretty clothing have to do with having a sexual preference for men? Our gender expectations must be really worn in if we think so simply as this: girls like girly things, but like to have sex with guys. If a guy likes girly things, then he's trying to be a girl, and therefore likes to have sex with guys.
Ironically, by calling this man out as a homosexual, they are simultaneously denying the existence of homosexuality - in women, namely, that a girl could like girly things and like to have sex with girls, not guys (see separating sex, gender, and orientation). But I guess, if you're so entrenched in your gender norms, then you must believe that homosexuality works like this: gays like feminine men and lesbians like masculine women. See, in this mindset, even homosexuality conforms to the heteronormative standard of coupling - that one person has to be the man and one person has to be the woman, and that for two people to be sexually attracted to each other, they must be of opposite gender, no matter what sex they are.
Or something like that? What's with all the assumptions? Why must we assume that things happen a certain way? Because we see one path being chosen the majority of times? We assume that's 'just the way things are', and that everything else is "queer" and odd, and even then, the only way to understand them is to rearrange them in terms of the system we're familiar with? Where is there room for tolerance and diversity in this framework? You can't have tolerance and diversity without a fundamental respect for nonconformity, which is the opposite of conservatism.