It's terrible, but it was one of those things that was going to attract some nut eventually. If what you write annoys people enough that they want you dead, at least you know there was some fundamental truth in your writing, as and it rubbed some major league a-holes the wrong way.
That's stupidly wrong. I am not saying that this is the case here, but when Hitler wrote about the Jews, if people were annoyed (to the point of attempted murder) about it, it does not mean he had "some fundamental truth" in it.
Afaik, Hitler wasn't attacked for what he wrote, per se. I'm not sure this invalidates the point.
These people that attack authors must have been disturbed enough, by being exposed to concepts they find distasteful, that they lash out. They attempt to transfer their inability to cope, with what they imagine the book will do to others, to the author in a misguided attempt to diminish their own pain and/or to gain notoriety for doing so, on other people's behalf.