Jim Bell's comment:     I think Trump's team has a valid argument here.  Those social media companies have been acting as 'state actors' by apparently taking orders from government.  Some of the statements they've made confirm that.

There's some little detail you seem to be missing tho. What you call "trump's team" is the government. And there are a few more details you are missing. No, there's no actual private sector in the US and yes, all big business are 'state actors' - just branches of the US state.