This is a thought that just popped up in my mind so it won't be super well researched or thought out. Bare with me if you're willing.

In developmental psychology, humans go through different age-related stages from infancy to childhood, teenages, young adulthood and mid-late adulthood. People are faced with certain challenges they have to adress to move on to the next stage. They're stuck in that stage if they don't, even if they grow older. Oftentimes this includes butting your head against a metaphorical wall until you feel forced to approach things in a different way.

The teenages come before adulthood and are a time of rebellion, independence, assertion of boundaries and becoming more aware to social power structures (who's popular in school etc.) as well as a sexual awakening.

The toxic masculinty idea suppresses and shames all of this progress through the insistence on the need for male compliance, gynocentrism (men's live to serve women), as well as shaming male assertiveness, competetiveness and ambition.

Men aren't just made to be Nice Guys, but eternal teenagers. Teenage boys, and even young men can't even finish growing up until they reject society's gynocentric programming.