what you describe is basically just Reddit, but with the people nobody wants to talk to on Reddit ... so mostly just the people you don't want to talk to on Reddit talking to each other,which has no mass appeal
I personally seek the most undesirable opinions in the depths of the worst comment sections - because there's knowledge about the world to be gleaned from all of that that I'll use as a competitive advantage against someone who couldn't be bothered to read something "icky" for a few seconds.
Competitive advantage?
What secret wisdom, exactly, do you think the racists, pedos and trolls of the web possess and casually discuss that would give you anything of the sort?
People already know what such groups believe and how little value they add to society. They're not the fucking Illuminati, and you're not breaking new ground by seeking them out.
I use HN with showdead on by default, and I sometimes post a userscript for people to uncensor comments and I've complained about the greying out of downvoted comments often ... I understand wanting to read everything and make your own decisions about what's worth reading rather than have others make them for you. However, most of what winds up flagged deserves to be.
Look at the flagged comment at the bottom of this thread, for example. It's just a rant against the "global socialist LEFT." There's nothing there that no one has read before. Even if you agree with the "validity" of the opinion, it's just stereotypical anti-leftist edgelord nonsense.
And now and then, albeit rarely, perfectly legitimate and inoffensive comments do get flagged. I try to vouch them when I can. But even then, I have yet to see anything I'd consider a true jewel in the rough.
There seems to be a trend among people to consider content that goes against the establishment to be inherently more valuable than that which goes with it, as if offensiveness maps to truth. Seek the bottom of the barrel out if you want, but I think it's a mistake to expect enlightenment from it.
I'm not saying alternative viewpoints and free speech sites are all sugar and flowers, because they often are filled with deplorable content. I do feel, however, that they serve a purpose in providing alternatives to the corporate.
the real reason free speech forums don't exist isn't because "nobody" would use it. i suspect its merely the safest thing to do legally. nobody wants to get sued for some controversial content. simple as that.