Earlier quoted context omitted.
I'm not suggesting that I've stumbled into some new idea. I'm trying to understand what people mean when they say "free speech platform". It seems to be a get out of jail free card of sorts. "Free speech" without any limits obviously doesn't work. Where are the limits of the parent comment? The devil is in the details.
Twitter, Facebook etc. are communication platforms in the same way the postal service, telephone system, etc are communications platforms. Communication platforms in the US should adhere to the US constitution.
Isn't this where the entire problem is coming from? If this were a state run service, we know the answer and can apply it easily.
The confusion is coming entirely from it being something other than the state.