[Govindae]

This is a general NLP problem. People use language in more complicated ways than direct literal encoding. In the general case, it's a very hard problem, but hate specifically may not be so difficult.

People tend not to use phrases like "kill all the" in unambiguous ways.

[belovedeagle]

However, a significant (not large, significant) proportion of Americans believe that the phrase "kill all the Nazis" is not hate because <reasons>, or at least is "justified hate", whatever that means.

[etplayer]

Although it's clearly hate, it is regarded as justified for reasons which some people agree with; a good read on this, from which I got the idea about the "subversive element" of society is Marcuse's essay Repressive Tolerance (1965), which you can find here: http://www.marcuse.org/herbert/pubs/60spubs/65repressivetole...