Are you trying to make a more specific claim than your post lets on? Maybe that it’s impossible to moderate without making some concession you don’t prefer? Or it’s impossible to moderate away certain kinds of things?
I would not have used that in my list.
It doesn't boil down to a "concession I don't prefer". The only thing you moderate are those things deemed illegal by the Federal government, anything else is fair game, which brings us a pretty large umbrella of discussion in which to engage. Some people don't want to engage in those discussions because they're hard and/or unpleasant. They not required to, and can freely leave them and ignore them. Allowing whiners who can't stand that people may have a controversial opinion that's at odds with their beliefs to have any power whatsoever is a fast track to failure on multiple levels.
People have block tools; they need to learn to use them.
Why?
It is certainly legal in the USA to be a KKK member as long as you aren't participating in the domestic terrorism. Yet I have no interest in conversation with KKK members and would will choose to freely leave websites where they hang out. So many people agree with me that a website owner decides he needs the traffic of anti-KKK people and starts banning legal Klan members.
Why must the website owner keep Klan members who have not broken any laws? Why should everything besides what is deemed illegal by the federal government be fair game?
They did leave, and then they made the new space where those discussion are not tolerated. We are talking inside one of such places.
Some people don't want to understand that there are discussion places which limit certain topics. They are not required to, and can freely leave and ignore them. They have plenty of other places where uncensored discussions can occur.
Twitter and Facebook aren't such spaces.
They're both based on models of unlimited growth, which means you're going to have unlimited viewpoints, which means you're going to have to #DealWithIt.
What you want, can be done on Hacker News because we're a focused community and most of us all have similar jobs, come from similar backgrounds, etc., or at least, there's enough of us that work in tech and enough of us that went to good schools that we're a more or less cohesive community with fairly similar values.
You don't have that with 5 billion users, sorry.
I'm guessing you mean the US Federal government, not the Federal government of China, or any of the many others around the world. For a global network, why should the US government's rules be more important than others? Or should networks be restricted to one country only?