Twitter and Facebook are not being compelled to speak. They host others' speech. No one thinks that when Donald Trump tweeted it was really Twitter's message, just like they don't think Apple is speaking when an Antifa thug uses an iPhone or that Microsoft is speaking when a neo-Nazi uses Outlook.
If AT&T just started banning Democrats when they expressed standard issue Democrat political views, you don't think there'd be a problem? Of course, there would. People would lose their shit because no one thinks AT&T is speaking when Democrats use their service to communicate their abhorrent views.
Moreover, Facebook and Twitter and YouTube advertise themselves as places where people can discuss what they want and then, in violation of the covenant of good faith and fair dealing implied into their terms of service (and every contract), selectively censor political speech they don't like and refuse to tell you how you violated their terms of service. If they want to limit you to cat pictures or videos of you dumping a bucket of ice water on your head they should be upfront about that.
Instead, Twitter, for example, holds itself out as a "an open service that’s home to a world of diverse people, perspectives, ideas, and information." Facebook is a social network, or "an online community of individuals who exchange messages, share information, and, in some cases, cooperate on joint activities." That's all people want to do.
What Twitter and Facebook and YouTube don't do is advertise as places you can submit messages and if they're interesting enough then it'll be published in their finite space - which is how newspapers work. You can post what you like and then if some troll complains that you aren't woke enough, they'll ban you until you grovel enough to be allowed back in. Or they won't. It doesn't really matter. They don't edit posts at all. There's no editorial discretion. If they decide you were naughty because of your politics, then you're done and they won't tell you why.