It's like "censorship is OK if a private company does it". This makes a bit of sense if you're attacking a Libertarian, but for left wingers to earnestly think that private companies should have the right to shut down discussion they don't like is very odd.
Sometimes I worry that large portions of online debate has been overrun by people making claims they don't really believe because they're a bad slippery slope take on the views of the people they disagree with; and sometimes people have even started to buy the deliberately bad arguments their side has created.
How should one tell the difference?
> think that private companies should have the right to shut down discussion they don't like
That's a perverse take on supporting 1st amendment rights. Do you believe that right-wingers in turn believe that private companies should be forced to serve users and content they don't want to?