> Youtube doesn’t have any kind of monopoly on posting videos to the internet

Of course they do. There are channels that can be removed that would instantly lose access to millions of monthly viewers that can't practically be replaced anywhere. They have a monopoly on that type of reach (the most important type), and especially when these platforms decide to blacklist in concert.

> now that they’ve done so they should no longer be allowed to moderate and curate content

Yes, because once your business decisions have the power to decide who gets elected President, for example, it's in a different class and has to be regulated differently than a corner flower shop. There are many examples of laws and regulations that apply to business based on size.

> what is this extremely strong claim based on? youtube is just one of an endless series of options for posting videos on the internet

Again, it's not one of endless, it is entirely unique -- for many channels, their reach on YouTube is not replaceable anywhere. That's like saying, AT&T can shut off your phone service for your political opinions because you can always go meet someone in person to talk. That's simply not how we've historically agreed to interpret the obligations of massive communications platforms, and there's a very good reason for that.

I don't want who gets to speak to the public decided by some faceless, unelected tech oligarchs. That's a dystopia. "They only get to decide if you easily get access to an audience of millions, you can always get an audience of 5" is a deeply flawed argument.