using prohibition of CP as an example is a very weak argument, generally speaking nude photos are said to be the speech of the person in the photo's they give the permission for them to be distributed (or not), children are incapable to give this consent thus the prohibition of CP is not censorship in the way you are attempting to conflate it here.

this si also why "revenge porn" is illegal, the person distributing the porn is NOT the speaker, the person in the photo;s is, and it is for them to control how that is distributed.

As to Germany's censorship of Nazi imagery, and holocaust denial, I believe the better path is the path the OP outlines where debate and open dialog is a better path and government laws. so I disagree that is an example of "good censorship"