Sorry for thread hijacking. I thought it was an interesting related point, related because the answer to your question is that men are sexually absolute, and that property is also responsible for other situations, the transgender one being the example that came to mind.

Thanks for laying out your actual argument and premise for this thread.  If a girl has sex with a girl, that is gay.... the girls are gay.  If a guy is watching this, since the objects of his desire are both girls, the guy watching this is not at all gay.  If I guy watches two men having sex, the watcher is definitely gay because where can he avert his eyes to?