This in a nutshell.
We've only watched the first three episodes as the third one left my DH speechless and quite affected. We have a toddler DD and a boy on the way so not dealing with any of this yet, but worried about it all.
DH grew up with a very hands-on DF as his DM was the higher earner which was probably less commonplace in the 90s. He's in no way sexist and is worried about social media influences on young men. A lot of his teenage experiences that he talks to me about - typical 12-16 year old boy stuff I guess - are things you still see and hear, even if shocking/gross to me (I was sheltered), but with a good male influence (DF) and no social media or Internet at hand 24/7 (we're just old enough to have missed this - smartphones/Facebook came out when we 17/18), he made it through unscathed. We can both see that boys with no support at home - i.e. modelling of behaviour from good men (and not just dads), coupled with bad influences on the net - are probably going to struggle. I think the absence of just one of these things may not be the end of the world but both would be a massive issue.
What struck me about episode 3 was that even though Jamie's dad is a constant presence, Jamie couldn't say much about his personality other than he's "masculine" and could talk about episodes of anger. A man who hides his emotions from his son can't teach that son how to deal with both positive and negative emotion, whether that's rejection, failure, joy, love etc.
I think the issue is that as women have caught up in all the ways that made men exceptional, men have done very little to match us - mainly, lots still don't put any effort into interpersonal relationships, especially family ones, or into building their own "village" like women do.
Boys and men who struggle with the idea of female equality and feminism are probably left feeling vulnerable that if it all goes wrong for them, they have little to fall back on and no community support. The "manosphere" then becomes this in place of real-life relationships.
I fear that violence amongst young men has increased because they spend so much time online that they don't experience geniune human emotion and don't actually see their victims as real human beings. It's scary.