The owners of the platform. They are not a public service nor to they have to pretend to be one.
But they do pretend that, all the time. They are a common carrier when it suits them and a publisher with editorial control when it suits them. That’s not reasonable and they must be forced to choose one or the other.
They bought into it. They are pretenders who, for the first time in recorded history, are able to perform a massive product recall in the name of censorship without incurring backlash on a scale that would cause bankruptcy or riots.
To wish away all that context in the name of "digital" is a fool's errand.
YouTube essentially has a monopoly on video. Monopolies and other actors can be forced to comply with public space laws or to respect principles that normally apply only to the government.
https://en.wikipedia.org/wiki/United_States_v._Microsoft_Cor....
Just because someone can run a small-time operation out of their garage, doesn't mean another company doesn't have a monopoly.
But then again I'm old fashioned and like to read about stuff on some web site and then click to whatever video hosting site they use.