As a queer woman in lesbian bars I've experienced the opposite of your story. All I can say is that straight guys, I could usually tell why they were there. Some just lived in the neighborhood, it was their local watering hole, and never bothered anybody or hit on anyone. Some came along with their lesbian friends. The only time I had a problem with straight guys in a lesbian bar is if they were hitting on the women there. So, if I'd met you in one of these bars, I'd be ok with you. I much prefer mixed bars. More variety, more open-mindedness. And the mixed softball teams are way more fun. The one thing about straight women going to gay/lesbian bars is that lesbians have a much harder time figuring out which women are straight, and who is gay. You can't always tell just by looking. (Male sexuality, I've found, is much more overt, direct, while female sexuality is more subterfuge-like.)