EDIT: Brian Molko, infidel.
OMG lieK YUS MAi nAeM isS LETO buT pOEPLE caLl me LEet. ^_^ B 4 T|-|E 51|_ |_ Y |_ /-\ /\/ G \/\ /-\ G E
Now to the seriousness...
People commonly associate sexualities other than heterosexual to be sexually obsessive. For example:
"You're gay! You like to take it up the ass!"
Whereas they don't just enjoy the occasional gaybumsecks, they actually have feelings for people who belong to their sex. People getting me here?
So when the people think "You're bi! You're so desperate that when a girl rejects you you'll **** anything!", they again don't consider the love thing.