You say:

Nevertheless, the thought or sight of sexual affection between men is still unsettling to me, as it is to virtually every heterosexual male I know, however tolerant toward gays he may be. And why not? Homosexual love goes against our intrinsic sexual nature.

I really don’t think this is the case. Many men are culturally conditioned to find same-sex affection “unsettling,” but in other cultures it’s common for men to hold hands or even kiss. Suggesting that it’s inevitable for men to be “unsettled” by this leads to a kind of confirmation bias — other straight men get it into their heads that they “should” feel unsettled, and they don’t want to be the one to admit that it doesn’t really bother them.

While different people may have different levels of intimacy that they’re comfortable with, I don’t think making blanket statements about what all straight men feel is helpful. Our “intrinsic sexual nature” can vary a lot depending on culture, context, and conditioning.