There is no such thing as harmful content. There are only harmful consumers of content. Removal of any amount or type of content can not rehabilitate these harmful consumers. For as long as they lack the motive and personal integrity to practice critical thinking on a constant and ongoing basis, no content can ever be safe from them. They will be harmed by even the most direct, fact-based, and honest content. Their interpretation of it will be wrong, driven by their motives and desire for a particular thing to be true or false, and even that honest and direct content will be called for removal. This isn't a trite or insignificant observation, I think it is the whole heart of the issue. In one audience of people, there is a madman ranting on a corner about anti-Semitism and being ignored. In another, he is raised on their shoulders and made a leader. The difference is not the availability of the 'bad content.' The difference is the willingness (some might argue ability, but I think critical thinking is such a basic and simple skill that almost all, including children, are capable of it) of the audience to practice critical thinking. And without that willingness, nothing can be done.