On the broader topic, breaking up Youtube, Facebook and the like is entirely desirable but would probably be pointless unfortunately. Increases in copyright zeal make a new competitor to YouTube impossible and the network effect guarantees both theirs and Faceebook's dominance. In light of this, I imagine the only solution is to legislatively guarantee an uncensored platform on essentially the same logic that requires net-neutrality.
But I point out that "uncensored" is entirely ambiguous. For better or worse, the vast mass of people want and expect it with the percentage very dependent on the particular item. From archaic restrictions on "dirty" words over radio waves through to displays of sex to recruiting terrorists to national secrets to doxing individuals to child pornography.
For right or wrong, somewhere, the public, legislators and each individual decides to draw a line. In addition, for short periods of crisis or certain locations or certain influencers, the line can move. The often misused example of yelling fire in a theater comes to mind but a national leader harmfully using false announcements to raise the value of stock he owns would be an example. More relevant would be the South African leader who zealously told his people AIDS can only come from drug abuse.
On the YouTube issue, for right or wrong, they drew the line in a place some would not. I would guess because they view such messaging as unusually fatal in the short term and they don't want to be a part of it. And that they could not find any simple judgement criterion that would do what they want without doing too much and yet be palatable world wide. If we legally require them to carry every upload regardless of content then it will lift all their burdens. But it will certainly create very real problems for others.
My point is that the issue is far more complex than bumper sticker sized answers.