Some straight guys are trying too hard to prove something to someone...
Oh yeah? What do you think they are trying to prove?
They want everyone to think they are straight because they don't want the reputation of being gay.
You should respect people and their sexual preferences, as you want yours to be respected. It's wrong to make assumptions about people you don't know. Everyone's mentality, likes, and dislikes is created by their unique view of the world and that should be respected.
I have nothing against gays, I'm just stating facts about those straight guys in school.
I'm glad that you are accepting of gay people, but you should try not to judge the other guys in school. You really can't assume that they're trying to prove something. They're probably just trying to fit in like everyone else.