I think one of the problems are there because many straight girls go to gay clubs & bars. I know someone who hit on another girl in a gay club only to get punched in the face by the girl and then had her shouting "you get your filthy hands off of me, I don't to women!" at her.
I think there's often a little apprehension to talk to new people, people stick in their own groups. I know my friend does now after that little incident.
