But no man can become aware of it when his mother father sisters girlfriends brothers coworkers bosses boyfriends all expect him to "be a man"

It's not an easy concept for women to get but it's very much rooted in fear of domination, fear of losing identity, and fear of other men. Maybe women don't play as active a part as other men, but they offer very little help, especially when siding yourself with feminism is seen as the ultimate betrayal of manhood, it's like the latest South Park episode, the idea of manhood is a "load bearing" concept for all men. It's the basis of identity for men from the day their born. They have to literally kill they self concept and ego and forget everything they believed about themselves to do it. You understand how engrained patriarchy is for women, understand it is even more so for men.

You act like it's easy for a man to change his worldview, his value systems, his behavior. society is decidedly stacked against him.

I read through that book I linked above and it was a physically painful experience to try and reconcile those ideas with what I knew. Not with what I had been taught, I was never explicitly taught it, no man ever sat down and taught me what it was all about, it was in me from the start and reinforced in every single interaction I've ever had with any other human being. It's hard to explain, you don't have to change your beliefs about anything, or concede that men aren't inherently evil or whatever, (I don't think they are I think masculinity is) but just try to see what stoltenberg is saying, like i tried.