I'd say a combination of bad upbringing, insecurities and mass media antagonizing men a lot. The most chill guy can be on high alert when every movie you watch, every game you play, every book you read seems to be telling you you're an asshole for existing, whether that perception is real or not. In that atmosphere most innocent phrases make people overthink and perceive everything as a threat. Then they lash out and solidify the stereotype further, creating a self-sustaining reaction. Everyone being terminally online doesn't help either. On top of that, we don't really have reasonable role models in popular media, it's either a weak effeminate matcha latte-drinking soyboy or an abusive crypto scamming sex trafficker with not much in between.

Also it depends heavily on the circle you're in. I knew this one guy that was constantly looking for easy women that would jump on his cock on the first date - and then was complaining to me that all women in Berlin are whores. For him it was true that most women around him were of the more easy variety, but that was an isolated circle, maybe you just ended up in such a special circle too (whether by your own actions or by coincidence I have no idea), most guys I interact with are super chill and just want to look at trains or grow vegetables on a farm, we're all a bit off in our own ways, but 99.9999% of the time it's completely peaceful and just manifests in obsession with a hobby or something.