Some speech shuts down more expression than it opens up

Medium recently updated its policy to prohibit public shaming amongst other things (emphasis mine):

We want everyone to feel at home on Medium. This doesn’t mean you’re free from having your views challenged or your ideas re-characterized. Surprising or controversial views prompt exactly the kind of impassioned engagement we want here. But some speech shuts down more expression than it opens up, by causing silence, retreat, isolation, or intimidation. No one should feel any less than who they are from spending time here. And that’s where we decided to draw the line.

Bingo.