I've had three close friendships in my life with cis-straight men, two of them in my young adulthood, and wait ... Actually that's wrong. The second guy came out to me as gay decades later. He just stayed in the closet longer than I did.

The third friendship was with a coworker who became my business partner, and we were very close indeed, though he is actually 20 years younger than me. Even though he comes from quite a conservative family, and even though his parents are very (very very) homophobic, that sort of feeling just didn't "take" with him. I suppose that's because of how he grew up surrounded by peers (in a left-leaning city) for whom gay men are pretty ordinary.

Even so, we had issues to work through before we became very close. And letting my guard down only happened (I think) because he demonstrated that he wasn't afraid of sharing emotions and being vulnerable — traits I mostly don't associate with cis-straight men, not cis-straight men of my generation.

Anyway, sorry for rambling. Just thought I'd riff on the theme a bit.