Two ways this stops. One... define them in law as a 'platform' and not a 'publisher'. 2nd... they are NOT private companies when shares are traded on any Exchange. They're asking the 'public' to invest in their 'enterprise' so an expectation that they will uphold the rights of the people speaking on their platforms. If they want to censor speech then they have to take the company private... no public shares sold. This does two things, ensures rights are upheld and dries up the Left's cash cows.