The fact that speech can be distinguished from action does not in itself provide a reason to prioritize speech over action. Further, speech and action share a number of commonalities that there are good arguments made (by Susan Brison and Frederick Schauer, for instance) that the categorical difference between them rests on a philosophical error.
When one censors 'speech' they are really censoring thought. We just call it speech because that's the highest-bandwidth and lowest-latency mechanism us humans have to exchange our ideas. Eumemics and eugenics are two sides of the same coin, and I am very suspicious of people practicing either of them.
>When one censors 'speech' they are really censoring thought.
This is incorrect; we would surely say that a hypothetical person who cannot communicate at all, only absorb information, has thoughts, even if he has no speech. Further, thoughts are abstract, quite literally figments of the imagination. Speech is concrete as something we do with thought.
Just because someone is prohibited from, say, shouting that Jews should be rounded up and shot in a Jewish neighborhood it does not mean he cannot think it or even express the idea in other contexts. Speech is expressive in that it takes an abstract idea and makes it concrete through the action of speaking. Only certain forms of the expression of that idea, in certain contexts, would be prohibited.
A baseball player will get in trouble for swinging his bat on a busy street. He may still swing it at the stadium without any trouble. The act of swinging the bat hasn't been prohibited, only its specific 'expression', provided by its context as determined by time and place and who is around him. The player has freedom of bat-swinging. We have freedom of thought.
The idea that speech is not action is a relic of the doctrine of mind-body dualism, in which the effect of words on a listener is so substantially different that they are deemed lesser harms, because they affect the mind, not the body. Advances in neuroscience and philosophy have put dualism in hot water[0]. The law in several non-speech related areas has for a long time realized dualism is false, such as with the issue of the insanity defence and voluntary manslaughter.
