I bet this kind of mess is exactly what Zuck was trying to avoid when he didn't want to implement free speech restrictions or fact checking, because there's no solution to be found here - if you don't mark anti climate change material as false, your fact checkers are worthless and you're kowtowing to political/moneyed elements that are against it; and if you do, those elements will declare you biased, claim censorship, and seek political action. Of course, the other side will eventually seek political action in the first case as well, so there's no winning.

It's been entertaining to watch him gradually tightening the screws on speech over the years though, as if this kind of end result was ever in doubt. Outrage is stronger than principle, and the same thing can be seen on reddit at smaller scale (in the last decade reddit has banned, more or less in order - pedo-adjacent, hate, violence, harassment/doxing, gore and illegal commerce communities). I don't think there's any way for a social media giant to avoid these kinds of restrictions - communities will spring up around any kind of material, other people will find them and the news will write about them (with the amusing side effect that you'll get a Streisand effect if you don't shut it down due to the increased attention).

Facebook has it worse it seems - they're actively taking money from some of the groups they're restricting/fact-checking, which is all kinds of messy and filled with conflicts of interest. It seems the money is winning out, which is about what I'd expect. It'll be interesting to see how they resolve these issues in the coming years.