That is one place I don't think I'd ever want to visit, despite how crucial the history lesson is. I think I get enough of the lesson from a distance.
This is one of the reasons I agree with those philosophers who say the only thing that must not be tolerated is intolerance. If you let it take root, it silences everything else, and then people become capable of horror they thought was impossible.
It is a process of blurry lines because it is often that people take it to mean that everything should be tolerated and accepted. Bad ideas are bad ideas and they must be challenged.