I think you're taking things to an extreme.

Let's make some distinctions first.

On the one hand, you have violence and pornography, and also other crude content. There is nothing good about exposing children to these. It does not contribute to their growth or to their maturity as human beings and it is ridiculous to think it could. On the contrary, this content will cause psychological harm, causing distortions in their emotions, in their habituated appetites, in their self-understanding, and their understanding of normal relations. When deviance like that is tolerated, it shifts the Overton window. Children observe this tolerance and roll it into their sense of normality. Individuals suffer. The quality of society degrades substantially.

On the other hand, we have political agitation. This one is more difficult to define and handle, especially in a liberal democratic society. There are examples of obvious political agitation, of course, but children should generally not be exposed to political agitation at all, except as a subject matter at an age appropriate level and in an appropriate pedagogic setting. Children don't have the intellectual or emotional maturity to examine such material in the wild on their own where they would be at the mercy of unscrupulous adult manipulators who couldn't care less about the well-being of children. (Ask yourself what kind of person would want to involve children in their political agitation to begin with.)

So, there's a big difference between common sense things like these and coddling children. We want to prepare children for life, not teach them adaptation to depravity. You throw them into the filth of social and psychological pathology. Neither violence nor pornography should be normalized even in the adult world - it is harmful to the adults who consume it as well - so the idea that we should prepare children for life in some violent and twisted pornland is preposterous. Nobody has to put up with that garbage, and the law should be making sure they don't.