I find this whole debate fascinating and depressing in equal measure. I have a sort of academic interest in it, as a teacher and having studied a lot of gender and childhood-related topics as part of an MA a few years ago, but also more recently a personal interest as parent to a 6-year-old DD.
In part the current issues surrounding boys and young men undoubtedly stem from access to porn and excessive internet use. But the conditioning runs far deeper than that and starts much earlier. Parenting has changed dramatically since my own childhood; as a primary teacher a decade or so ago I was surprised at how gender stereotypes were becoming more rather than less ingrained among the small children I was teaching - clothing was coded pink or blue; Disney princesses for girls were everywhere and I had several worried Dads at parents' evening fretting that their sons would never be 'proper men' because they disliked football and enjoyed Lego and drawing. At the time online campaigns like 'Pink Stinks' and 'Let Toys Be Toys' were sounding the alarm about this stuff, but their concerns sound really pretty quaint now. I remember at the time there was also a spate of TV documentaries about how gender stereotypes played out in parenting/educatjon, so it was clearly part of the zeitgeist.
Roll on a few years, and by the time my own daughter was born the gender conditioning had ramped up considerably, starting with the gender reveal party trend and progressing through to highly stereotyped birthday parties (dinosaurs, football and Pokémon for boys; princesses, mermaids and unicorns for girls) and separate preschool activities for boys (football) and ballet (girls) - for four years now my daughter has been the lone girl in her Saturday football class, and we're in supposedly liberal north London.
While it was a fairly standard thing, when I was teaching, for at least a few of the boys in my classes to prefer to play with the girls, in my DD's school the sexes have been strictly delineated from the outset and exist almost in two separate bubbles, seldom interacting. 'Boys will be boys' prevails, and lazy gender stereotypes about boys being better at maths and girls being more docile are thrown about constantly by parents. It's all incredibly different from my own experience of growing up in the '80s and '90s, and it feels like we've regressed in a lot of ways.
I spend a lot of time working with children at the upper end of the primary age range, and can confirm several PP's reports of boys making sexual noises and porn/Andrew Tate-related 'banter' even in Year 6. The upshot of all of this is that we've decided we'll be sending DD to a girls' school for secondary.