Twitter, Facebook, et al just excluded leading conservative voices from the public square.
They are a private company that needs to do business to stay alive. Other companies can choose not to do business with them based on the content that's on their site. If they fail to satisfy their customers, they die.
They cannot satisfy the whims of those who pay nothing and demand a megaphone. They owe you, and your beliefs, nothing.
Maybe if you (or I) were banned from HN, no big deal, find some other corner of the Internet to shout from. FB and Twitter are the modern public fora however, they have through moats or whatever business tactics, made other fora far less significant, and in terms of discussion space they are a very big deal. You might be correctly repeating legal principles as they appear in last year's hornbook, however, the books will eventually change.
If Cloudflare and Google together delisted and deplatformed anyone repeating any words of the President or major conservative leaders -- that would undermine a core tenet of our democratic society. That would be an obvious affront to first principles. I'm not sure FB and Twitter are greatly removed from that hypothetical.
So is the premise of your argument that we should be protecting the less internet savvy from having to learn how to browse the web?
Give me a break. FB/TW shouldn't be required to uphold the public's ability to communicate.
If I build the biggest coffee shop my small town has ever seen and it becomes ridiculously popular, is it the new public square and I'm no longer allowed to kick out people for being assholes?
This "big website is popular so now we must treat it as public space" is a take that I see kicked around but has lots of holes in it.
Frankly, it makes smells like bullshit.