We (the public at large) need to have a discussion about when a private entity like facebook, twitter, etc, become so big that they essentially -are- public discourse. A lot of people treat these private entities like they're public. But they are not. As long as they follow US law, twitter can do whatever it wants. Yet people are shocked when twitter starts hiding tweets, or when facebook chooses to do nothing at all.
"Cancel culture" has nothing to do with the government, nor free speech. Free Speech does not protect you from criticisms or ridicule by other citizens, regardless if you think that's correct or not.
I don't know what the solution here is to cancel culture, other than speaking with your wallet. I fully blame twitter for conditioning people to only digest things in 140 characters or less, which makes discussing contentious topics very difficult or straight up impossible. I blame controversy-averse businesses that have no spine, and dismiss employees over some people angrily tweeting, who will move onto something else in a few weeks anyway.
I also blame people who specifically look for these things in order to "destroy" someone, as if someone can never change their opinion. I think cancel culture has absolutely nothing to do with ending sexism, etc, because all it does is train people to be private with their thoughts. If you view someone being sexist, etc, as "being sick", then the "doctors" are telling them to go die alone, instead of tending to them. How does that achieve equality?
I specifically limit a lot of what I potentially talk about online because it's not worth someone digging through it looking for 1 or 2 out of context sentences and making a stink about it.