I think what straight guys experience at gay clubs is a lot like what most women have to put up with when they go out. Most guys are the same, gay or straight. Basically they are out looking at and pursuing sexually attractive guys/girls to hook up. Now in a straight club it is the women you hear complaining about how guys don't know when to stop, how annoying it is to have guys you are not interested in hitting on you all night. Well now, the straight guy heads over to a club where there are alot of gay men and suddenly he is getting a taste of his own medicine. Now he is the one being pursued instead of the one doing the pursuing. I can see how that might be unnerving. I think that no matter how progressive people are, it will still be hard for the gay/straight crowd to truly mix at clubs because of this.