Free speech has limits. You aren’t allowed to shout “fire” in a crowded theatre because someone’s probably going to get hurt. Your right to say what you like is trumped by your responsibility to stop me being trampled to death by a stampede of panicked theatre-goers. Death threats; rape threats; bomb threats; online abuse that drives someone to suicide – these are all things that free speech doesn’t cover – and which aren’t appropriate to defend in its name.
Erm, those things are indeed covered by free speech. Or at least should be. They might all be very bad things, they might even fall foul of other laws, but they are indeed things that people should be free to say–even if they then suffer the punishment of those other laws.