One of the guys on my swim team is gay and we over many, many beers had a similar discussion one time. The summary was, most of the guys that he knew and hung out with just didn't really find straight guys sexually attractive. They could appreciate hot guys, but didn't really want to do anything. Best way I can relate it is if I see an attractive woman who is beautiful, but not my cup of tea so to speak.
Reading further into that, it's pretty likely that you are not getting checked out at the urinal, unless of course you are in a gay bar... Then all bets are off.
