There is place like that already: 4chan. How is that working so far as a public square?
It's kind of like pointing at an institution run by edgy, lonely teenagers and asking, "How is that working so far as a ${institution_type}?"
My argument is that there is a place online where anyone can go and express an idea and challenge ideas of other’s. That place is (among others) 4chan. It’s not some obscure personal blog, it’s a large and influential platform. Is it working as a public square? Are you using it to challenge ideas you disagree with?
If someone says something dumb you call them a slur and move on. So yeah, actually.