bullshit.
All you know is what most straight men CLAIM about their preferences.
Obviously, in a society that can demonize homosexual behavior, most men will present themselves as being exclusively heterosexual.
But research shows a very different picture, with only around 10% of the male population showing no sign of arousal at gay imagery.
Witness how many men claiming 100% straight on this very site express interest in viewing if not fantasizing about other cocks, and realize that even those claiming zero interest are, nevertheless, ON THIS SITE.
When assured of total anonymity, the number of straight males who will admit to homosexual desires or experiences goes up starkly... Kinsey reporting 1/3 of all males admitting to actual homosexual acts, and another fifth admitting to fantasies.
All real evidence supports the notion that human males are, essentially, Generally sexual, and that they fall individually on a bell curve from 10% exclusively heterosexual to 10% exclusively homosexual, with the majority some admixture in between.