Even though peaceful anarchy is not reachable, it should be allowed to think, talk, write and publish about that ideal.
Anything that is purely information doesn't harm anyone.
Drawing and writing anything online should be allowed.
Even if someone writes "Kill all Germans.", so what? Somebody else will write "Don't kill all Germans."
Even drawing naked children should be allowed like it is in Japan. Doesn't that in fact help harm the market for actual child raping and filming? Even that material should be considered evidence *of* the crime rather than the crime itself.
What else in extreme cases did I forget? My overall point remains: Allow all writings and drawing on the Internet. Completely free flow of information. This isn't even anarchy. This is just a logical extension of the Free Speech argument from classical liberalism.