[fzeroracer]

Your comment goes against what you originally said then, which is that you 'don't want some wanker at Twitter or Facebook office' to decide that. You're making a concession that you do want them to decide SOME content that is by default blocked, which then this becomes a matter of degrees. Some people would disagree with your stance and think that it still violates free speech, hence Parler/Gab etc. Plenty of disturbing content is not illegal, which is where the gray area of moderation comes into play.

Even if you don't subscribe to people that post that, there's still the issue of network effects. They subscribe to someone that subscribes to someone that subscribes to someone that posts a beheading video that gains popularity, and so the algorithm prioritizes that traffic because it's within your graph. You can easily notice these effects just on Twitter if you pay attention closely to what it decides to show you.