First of all: I am most certainly NOT a homophobic and some gay/lesbian/bisexual people are my best friends.
Ok, for most gay people that I've met you can easily tell that they aren't really guys on the inside. The things they wear, the way they talk, the way they carry themselves. I know that is very stereotypical, but that's the way it is for most gay men. If you can't obviously tell that he likes guys, then just listen to what EmoWolfie has to say up there!