I am tired of being told "they are private companies" as if that ends the discussion. There are valid questions as to whether they are abusing monopoly power and also if they have violated provisions of internet law that grants them immunity from lawsuits on the ground that they are not exercising editorial control.
Even if their actions are technically legal, Trump is making a huge mistake in not imposing regulation on them. He has ample means to do so without congress. For example, the FCC or FTC could impose a mandate to serve users fairly and without bias. Banks, insurance companies and mortgage companies are private too and they face all kinds of regulation as to what they can do in rejecting business.
Trump's election owed a lot to independent internet commentators and meme creators. The big tech and social media monopolists have clearly vowed not to allow something like that to happen again. The establishment republicans have already surrendered but most of them are not unhappy about getting right wing voices banned. Now that more mainstream people are getting banned, suddenly they are whining about it, but they are so conflicted and bought off, they will do nothing. It's up to Trump and, as usual, he is all talk and no action.