Anonymous domains...
...are an interesting conundrum. If you allow them, they can be used to shield spammers and scammers... if you don't allow them (and don't allow bulletproof hosting services), you cut off the only means some people have to express dissent anonymously.
As much as I detest scammers and spammers, I'm inclined to think that the capability for truly (or at least, very much) anonymous domain registration and hosting is necessary.
There might be one way to solve the problem, though - disallow registration of massive numbers of domains at the same time, something which is extremely useful to scammers and irrelevant to pretty much everybody else. I'm not sure whether that's practical, though...