Because those girls are seen beneath them and easier to to do anything they want with them since they don't see them as equals. For guys, when they meet a girl equal to them it means they have to put work and ect into it to get her, while dumb slutty kinds are easy to obtain and don't really...
Homosexuality is defined as attraction and/or wanting to be with same sex. Playing with your butthole although may be bit weird, does not mean your gay.