I think platform owners should have the right to decide what content they want and don't want on their platform, and I would say that not blocking can definitel

I think platform owners should have the right to decide what content they want and don't want on their platform, and I would say that not blocking can definitely amount to endorsing depending on the situation. When Reddit was under fire for the child porn flourishing on the site, if they hadn't taken action, they would have (rightly) been seen as endorsing it. I don't see how this concept of a purely neutral platform that is adamant about allowing any kind of content is a necessary or useful thing. At the very least I don't think it should be mandated that platform companies meet that standard or even attempt to. The ones that do descend into toxicity very quickly. It's not clear to me what value is really being preserved there, and from my perspective the level of censorship in the US in 2020 is generally toeing a pretty good line, i.e. not sliding down a slippery Orwellian slope (though no doubt in a country of 300 million you can find a fair few concerning counterexamples).