The US government censors child pornography, details of nuclear weapon designs, etc., with penalty of imprisonment instead of just having a post deleted. If you care so much about censorship, why do you not focus your efforts on it instead? (Not to mention other countries like China and North Korea.)

One reason would be if you believe that the act of suppressing a significant point of discussion of possible actions of an FAI matters rather a lot. "Don't talk about the possibility of my 'friendly' AI torturing people" isn't something that ought to engender confidence in a friendliness researcher.