In fact, forget engaging with human beings -- try a library?
>4chan is, paradoxically, one of the most genuine, purest human forum experience you can get
This is unimpeachably true, imo. There's something equal parts magical and horrible about unfiltered humanity, especially after living in digital mind-prisons where we have to be careful about not angering our advertiser jailers while self-aggrandizing and posturing on a feed instead of actually talking directly to people, all of us anonymous and shed of baggage and upvotes and reputation.
I still believe this, even after I stopped using 4chan cuz edgy teen humor gets old after a while and the horrible parts of it start being unhealthy. :p Modern "social" media makes me miss it sometimes though.
But it's not the only place. Nor is it even a main place. Nor is it a place to find high-quality versions of any of these things.
There are far better places to find opposing, passionate points of view. Far better sources for creativity and weird things, far better places to find a wide range of views.
The way you write, it basically sounds like you're mistaking 4chan for the internet as a whole. Trust me -- if 4chan disappeared, there's still practically an infinity of things written that you couldn't think about.
Hell, forget the internet, you'll find an awful lot of them just in a research library. Especially from roughly the 1930's to the 1970's, artists, political theorists, and psychotherapists were coming up with a lot "edgier" stuff and ideas than you're probably even remotely aware of, just to pick a few areas.