Horrific violation of the basic rights to free speech.
I mean, here's a book that not only advocated for the violent overthrow of the US government but gave explicit instructions on how to do it: https://en.wikipedia.org/wiki/The_Anarchist_Cookbook
It is legal (and easily available in the United States), but not legal in many countries, which is dumb. While the FBI investigated the author and the book itself, they concluded that it falls well under the 1st amendment rights of Americans. Again, and I'm not sure how many times I need to point this out, America is really the only free country in the world.