Come on - you must realize that you don't actually believe your argument as a principle, you're just using it as an excuse because you want Sullivan silenced.
Good luck finding that. It's as if controversial opinion columns didn't exist before 2018. I couldn't even find an article with a list.
Our panopticon falters. Help me Landru! (Obligatory ST TOS reference, The Return Of The Archons)
Labor has market power as well, if it chooses to employ it. Somehow, I don't think a guild of columnists is going to amass to protect Sullivan, though.
As an aside: do you think it has ever once been persuasive to write something like "you must realize you don't mean what you say, but rather this other thing I'm convinced you think"?