"Public Square" online is a fallacy. A public square is typically thought of where someone grabs the attention of all passerby and is voicing their thoughts. Those thoughts voiced are short lived and can only be broadcast as far as the sound wave will carry them. Social media like twitter allows millions of people to spread their thoughts, commentary and keep them semi-permanently online for a long time, decade or more.
I never stated I was solving the problem of people saying racist things. I'm challenging the assumption that designing a new social media platform should repeat existing designs that have public content with public comments driven by advertisements. In my opinion if someone designs with that premise it will end up the same as the existing social media platforms we have today (with a side effect of new JS frameworks being borne).
Is this the only product design Tech has: public content and sell advertisements?