Joking aside, this is why social science is inherently intractable. The only way to mitigate is to educate citizens, not censorship or regulations. But education is not only hard, also highly profitable...
The poster's point was that commercial platforms must address the same issue of undesirables. People realized that allowing the government to prohibit certain forms of speech has the negative externality that governments also gain the power to regulate all speech. On the other hand, corporations can never feasibly have that much power. They can only limit speech on their own platform. There's always another place to speak freely if you wish.
This is why I find the "free speech" argument for not regulating internet comments intractable. It assumes that since we don't want governments regulating all speech, we don't want corporations regulating speech on their platform. But that simply doesn't make sense for idealogical reasons, which I believe was the top-level poster's point.
Facebook has more users than any government in the world.