Censorship, in the case of the protective entity of government, insofar as it provides the security, welfare, and economies that its people requires, is necessary in order to keep the stability of that government within acceptable limits.
Censorship based on personal belief values, with a purely subjective and flawed understanding of what certain media will definitely do to a child, and what that media has been associated with, is a much more sensitive issue. On the one hand, I can understand that it may be attributed to such reasons as simple distaste for the media at hand, on the other hand I can understand that a parent would want to keep a child from being influenced by that media. I do see the problem, though, that is evident in the wholesale banning of media based on the influence it will have on children: that the parent is failing in its duty to educate the child and understand the child's world.
I won't say I'm against all censorship -- some people simply just cannot be allowed certain information because of the sensitive nature of the information, and the possibility of misuse and abuse of that information -- but certainly there needs to be more incentive placed on the parent to understand the child not as being just its child, but also as a person who lives in a very different environment.