I think part of this is a result of toxic masculinity issues. I remember reading a comment by a trans man on how his friendships had changed after he transitioned, and while part of it was how his friendships changed with women he had been friends with before he even transitioned, he also talked about how his friendships with men were missing a major part that had made his friendships with women before he transitioned so deep - and that was emotional vulnerability. Similar to what you're saying, he found that it generally isn't socially acceptable for men to form true, emotional connections with other men outside of scenarios that emulate life or death situations. Things like hunting, or sports that were originally created to keep soldiers fit outside of war are acceptable situations for men to build that camaraderie. Outside of these kinds of scenarios though, men aren't allowed to be emotionally vulnerable with each other and make true friendships that go beyond a surface level, leaving them emotionally isolated and stunting their emotional growth and well-being. He also theorized that this is probably why men mistake women being friendly as them being flirtatious since women have that deep emotional connection in all their friendships, while men are only really allowed it with romantic partners, but that's outside the scope of this conversation.