I also agree with the opinion that if a man has sex with other men, then he is not st8 and there is at least some degree of bisexuality. I have noticed however that the "str8 fantasy" is very common among gay men so whatever floats our boat.
I have met and had sex with many men who refused to identify themselves as gay or bisexual. What I have detected is some sort of guilt to them as they consider that sex with a man makes them lesser men.
As far as pleasure is concerned, there were times that sex with those men was truly amazing, but there were also times when it was horrible. I have noticed that that insecurity about their sexuality (thinking that gay sex makes them lesser men) drives them to be more agressive which can be a turn on at times.
However most of them refuse or cannot show any sign of emotion, they treat you like a tool, they do not seem to care if you enjoy them and some of them also try to pretend that you are some sort of woman (for example, refering to me as a "woman" or having a "pussy"). Those are major turn-offs for me.
I also believe that people who consider sex with straight men to be better by default are aroused mostly by the "turning a straight guy on fantasy". I understand that the idea that a st8 guy would be so attracted by me that he would bend his sexual orientation for me is so arousing that makes sex more pleasurable.
This is the reason that there are so many "gay for pay" porn actors. They exploit the "straight man who fucks men" fantasy.
But we must be aware that this is just a fantasy. We are not actually "seducing" str8 men, as they are not completly str8. They just refuse to label themselves as gay or bisexual. Thus, having sex with those men does not make us special. We are not that irresistible. If it was not me, they would easily fuck another guy easily. In fact, I couldn't help but notice that those men are more eager to have sex with men than gay guys.