B-but what if people say mean things? :/
So is it morally allowable to discuss <abhorrent topic> online? Should it be law to allow or disallow <abhorrent topic>?
Who decides what the majority of people consider to be abhorrent?
There is a simple solution to this if you don't like the way they behave: stop using their product, and recommend others do the same.
Of course, your not using it doesn't prevent others from using it if they want to, but that's freedom of choice for you.
social media posts can be a single person communicating with millions.
the damage per unit of effort is much much lower for the unmoderated phone vs the unmoderated social