4chan has /pol/. 4chan inspired Gamergate, Pizzagate, QAnon and numerous incidents of extremist violence. Those other platforms mostly just spread and accelerate the toxic culture that originated on 4chan.
https://www.msn.com/en-us/news/technology/epstein-met-4chan-...
Internet starting with a 1000 4chans wouldn't create what we have today (you'll just get lots of small fringe groups), internet starting with a 1000 facebooks/twitters/... will always end in extremism of a big portion of the population.
4chan is where you go too far. 4chan users typically don't foster extremism, they are the extreme. They don't post pictures of young women, they post addresses and walkthroughs of their apartments.
It's easy to control for governments compared to facebook/reddit/... because it's just some boards, way better than massive amounts of posts creating a personal zone for everyone.