IMO, there is speech that needs to be regulated, and that is speech that promotes any kind of governance that would enslave the people. Like Communism. Or its ugly but only slightly less dangerous little brother, Socialism. The American constitution could not continue to exist if either of these types of governments were installed, so they both threaten our constitution.

That is totally unacceptable in a free society.

The same goes for any religious Theocracy - it has no place in a free society, and for good reason - it promotes enslavement to a religious dogma.

Also, totally unacceptable in a free society.

Speech promoting these things in a free country, is speech that seeks to destroy the democracy and the freedom of the people of that country to say what they want.

Any other speech is free speech, and anyone in a free country can say what they like. PERIOD.

Sometimes there are consequences for what we say, such as if we threaten to kill someone. So if someone says those types of threatening things, they may face a charge, because threatening someone with death can land the threat issuer some jail time.

If someone just doesn't like what someone said, they can move away, put their fingers in their ears or not pay attention, but they have no right to take some sort of revenge on the speaker.