you fail to understand that people can have very real and ernest friendships that are different from your presuppositions around friendship

What makes you think that? It's nice if you don't put on a front in different social settings, but many people absolutely do. Which in itself I find completely understandable. We are social animals and deeply dependent on being accepted and loved, and society certainly doesn't hold back with expectations, which most of us then try to meet in one way or another.

I tend to not talk about myself that much anyway (I also have a therapist, which may contribute to my not feeling like I need to), and when I'm with friends who do, I mostly listen

If that's what you prefer more power to you, just would be tragic if you did so because you felt pressured into it.

And it just so happens that society does put the expectation on men especially not to overshare, to rarely show vulnerability if at all, to be strong for others, to silently endure.

That doesn't mean men who adhere to those expectations can't legitimately have fun with their friends (or even feel like that's all they want from friendships).

And maybe you are 100% capable of chosing how open and trusting you are, devoid of all social expectations, I don't know you. Maybe you just so happen to arrive at a set of behaviours that match what society wants and expects from men. If not, this is something that we as a society have taken away and in a way continue to withhold from you. And that would indeed be sad, just because of how unfair that would be. It certainly is for the many people out there who are in fact incapable of this other kind of friendship (e.g. where you assign value to your feelings and experiences and want to share them) - not by an informed choice, but through subtle social pressure. That's what I meant originally.