Other people gave you enough arguments against censorship above. I'll just add that "Inciting violence, threats to ones well being or insults towards a group" are all quite vague and thus contradict the goal of having a clear ruleset.
Maybe, but probably more likely we'll just end up where media and public discourse just becomes slightly more civil, tones down insults and focueses a little more on substance to make its claims.
I similarly don't have a way to prove this would be the outcome, I admit. I rely on a different premise, that we're a reasonable democracy, and that just as we work to fight collusion and corruption, we'd manage to control abuse of such laws in cases where they'd be used to oppress and control in a non democratic way. I feel if you don't believe our society can do this, then we're doomed to lose our freedoms to an authoritative regime anyways.