Yes, but while the USA doesn't have "hate speech" even defined in the law, it does have the notion of "hate crime". Which does include incitation to violence, intimidation, bullying and really everything that's already illegal if they're motivate by race, color, religion, national origin, sexual orientation, gender, gender identity or disability.
And, for all his trolling otherwise, again, Elon did say 'as long as it's not illegal.' If it's actual incitation to genocide, I'm pretty sure it's illegal already.
So again, I'm not seeing some great threat, other than as some imaginary SF scenario by sad little twits who got butt-hurt that they no longer get an echo-chamber for their own views only. And that kinda is when you know that someone doesn't have an actual argument: when it's let's not deal with reality,
let's deal with some imaginary scenario in which verily everything they don't want to hear is an outright incitation to GENOCIDE. GENOCIDE, I tell ya