Im not sure I entirely agree with the idea that that sort of bullying is what happens in small close knit groups of guys. I've been privileged enough to interact with some of these close knit groups, up close and personal ,and either they were on their best behavior because I was present (unlikely) or they were just genuinely nice guys who showed how much they cared for one another without humiliating each other all the time.

Or maybe I missed it (but I don't think I did, since I've always paid close attention to stuff like that. I kinda have to.)

I'm talking about men of color here though, so maybe the dynamic is different with them, or its the same dynamic, and the actions just look different to me, but so far young white men are the only ones I've seen do this kind of thing, and its not all of them either, because I've seen some of them be very kind and generally respectful of their friends.