I always thought that the way content never gets deleted as a good thing. If a post was really bad people won't see it, but those interested in reading it (for whatever reasons) still can.
But I never considered it to be actually used for criminal activites... Now I don't know how I feel about it. Maybe there should be a way to remove that in some future hardfork before it becomes so much of a problem that it brings the whole blockchain into danger.