That is one example, that if true, I would agree with you is not appropriate: for straight or gay people. That is not indicative of gays more than it is of straight people. Them being gay had nothing to do with it. There is not a single outwardly behavior that defines all gay people. That is the kind of idea I am against. The fact that you bring up ONE example as your justification is absurd. "I met a white guy once and he called me a name, why are all white guys bullies?" that is basically what you're saying.

If they were doing something you wouldn't have noticed a straight couple doing, and you reacted that way, then you're in the wrong. Very few people would defend the behavior as you claim it: FOR ANYONE.