To be clear, incendiary, antisemitic, racist, discriminatory, hateful, antidemocratic, violence-glorifying statements and calls for riots must be refused by any media and immediately deleted from social media.
One does not need to go so far to be for the right for everyone to say everything as the great Noam Chomsky has suggested, but banning pronounced and even extreme opinion by blocking individual accounts is a mistake.
The downside is multiple:
People find ways to spread their views anyway. The communication will be pushed to areas invisible for the general public and overseers like media and authorities. Other people will not be confronted with the entirety of what people say, think, demand, plan. The unacceptable and despised views vanish from sight and consciousness. The chances to contradict and unmask are forfeited. The division, bubble, echo tendencies grow. Private companies play regulators.
The big danger is that extreme positions and activities will occur in the dark even more and people may forget they exist. Invisible, unknown enemies are created and supported unwillingly.
It is better to let everyone post and tweet on their accounts, mark the questionable ones and take the de facto incriminable ones out.