There's two different aspects to be considered here: What you seem to be mostly worried about is direct legal consequences to speech, like being imprisoned for saying the wrong thing. Protecting people from that is important, but freedom of opinion and expression is more than just that.
But more important than that is the societal aspect: censorship is ultimately a propaganda tool. You don't have to imprison people to silence ideas; simply hiding them from the public is more than enough.
The reason this is the more important of the two is because it is what influences public opinion. Propaganda is an incredibly powerful political tool and freedom of expression is, also an opposing force to it.
But more important than that is the societal aspect: censorship is ultimately a propaganda tool. You don't have to imprison people to silence ideas; simply hiding them from the public is more than enough.
The reason this is the more important of the two is because it is what influences public opinion. Propaganda is an incredibly powerful political tool and freedom of expression is, also an opposing force to it.