Honest answer (IANAL): it doesn’t have legal obligation to support all kinds of free speech. But in my opinion that’s because the governments fail to recognize these huge, influential social platforms for what they really are - utilities. They become pervasive and essential in lives of most people in the developed countries. And as such there should exist some checks and balances to make sure these platforms are not used to skew the opinion of the general public one way or another. Powerful people on both sides of political spectrum should not have direct lines to moderation teams “suggesting” what should be removed or suppressed, nor the moderators should act on their own accord when the speech in question isn’t explicitly violating any laws or site policies.

I know this might sound pretty idealistic but for anyone who thinks otherwise please entertain the possibility that such control could one day turn against you, your political candidate or your personal beliefs and suddenly it will be you who finds themselves in the crosshairs of censorship when there’s a story you believe should be brought up. It’s an ugly timeline that I don’t want to live in.