v6 is just as easy to censor as v4. Given the popularity of Veitnamese pho noodles over there, I don't think internet censorship is as important an objective as you estimate. Have you noticed how many Chinese tourists there are around the world? Not much you can do about internet when any of them could just pick up a newspaper.
My impression is that the Chinese government doesn’t care about a few people being able to access blocked content. What they want to do is prevent large social movements from forming via the mainstream internet.
