Freedom of speech is touted as a right. But rights come with inherent responsibilities. Twitter/Facebook/etc as private companies don't have to allow themselves to be used as political platforms, although if they are going to claim that as apolicy they should have banned him about 3 years ago.
As for the incitement, did you see the speech? What did you expect to happen when he told his supporters to march on the Capitol, seat of the government he is head of? That they'd all stand around drinking lattes and admiring each others Trump merchandise? What about the bit where he promised he'd be with them, but instead retreated from behind the bulletproof shield and went back to the White House? The following speeches were no better, full of questionable support and veiled threats, although the second one was clearly written by somebody else; somebody with a decent grasp of English