In my humble opinion, here's my view:
Women are encouraged in more "immoral" circles to be bisexual (not full-on lesbian). Immoral circles = college parties; strip clubs, porn world, swinger meet-ups, etc. This is not the case in conservative circles, although lesbian sex is not deemed quite as depraved as male homosexuality. So, point is: men keep all their same-sex attraction bottled up when they're younger. And, when you age, you start to care less what others thing. Put that together with a slightly more open-minded world in the age of Internet. Bingo! Not all are repressed gay men. Let them label themselves, should they feel a need. Otherwise, forget it. And for some, emotional attraction is the motivation, more so than physical attraction. But because of the nature of male sexuality, genital-based sex happens in order to fulfill emotional intimacy desires.
Interestingly, some of the older men looking for same-sex experiences are very, very masculine. They might take you on a hunting expedition and fuck you wild in bear country. Seriously.
At any rate, younger men are indeed much less homophobic than their fathers and grandfathers. No doubt about it. They compliment male physiques and some can even dare to say that another dude is hot without feeling eternally gay.
I've noticed, too, that swinger ads are becoming more into finding well-hung studs.
There is a niche in straight porn that is really growing in popularity, or so it seems: "meanbitches". This is just a mistress forcing you to suck on a big dildo, or get fucked up the ass. Or she'll even bring in a well-hung stud for you to suck on. The women heterosexualizes the event, making it not feel as gay. It's gay sex nonetheless! Though, many, if not all, of these dudes like pussy big-time. So the women is also a big turn-on. This helps straight men live out their gay fantasies.
That said, there are very small minority of men who just have zero attraction to men. These men are often strictly into lezzy porn, or all transsexual lesbians themselves.
Porn star Evan Stone loves the cuckholding scene, but there is no doubt that he loves eating and fucking pussy.
Great thread, by the way!