There are bountiful examples of regulated speech in the modern world and yet the world isn't only China and Russia.

Speech is regulated right here on this platform, where you clearly have no qualms with participating. Speech is regulated in Germany, where it is outright illegal to express Nazi-sympathizing opinions or to deny the Holocaust. Speech is regulated in the US, where you cannot shout "fire" in a crowded theater or promote investments you haven't disclosed your stake in.

Not all slopes are slippery.