The whole "end of free speech" issue comes not so much from the government sensor really (that's still firmly restricted by the first amendment) but from companies themselves banning any content or accounts that might get them sued.

Really? The early major moves (so stupidly transparent and to reinforce the concern and urgency) was to go after Facebook who agreed to appoint a government representative to their board. Which is unprecedented except in state-controlled entities. Threats have been made and lawsuits filed by Trump personally or his new attack dog the "DOJ" against most major media organizations including those who produce content and/or control distribution and algorithms. Many of the orgs have paid "fines" or tributes to the government in power to remain in favor and altered their content, presentation and/or coverage. This is naked violation of freedom of speech and press.

Back to the point: if enormous and otherwise powerful companies so easily fold--in a matter of months into an administration--there is no "independence" and government censor is hardly theoretical as you would present it, but already in place, and as such puts who defines "dangerous" in an unsustainably temptingly powerful position ripe for future abuse. This is existentially concerning no matter your political stripes as it's the end of the political experiment that was the US.