Perhaps what you are saying is that it is not good to make him a martyr in the eyes of his followers, much less to resurrect him long after he'd been discredited.
That, certainly. There are still a few holocaust deniers around, but there has never been much danger that this particular kind of historical revisionism would spread very widely, I don't think. I move in academic circles and I have never once run into it personally, anywhere.
I don't worry so much about making him into a martyr as criminalizing speech, even vile and offensive speech, which is tempting but can breed more problems than it solves.
When I look around at the faculty of American universities, at the people who shape our future citizens, I see no apparent Nazis at all, but I see huge numbers of leftists who demonize Israel and glorify Palestinian terrorists, and who for all intents and purposes spread a vile kind of antisemitism far and wide under cover of anti-Israelism. Even some of my leftist friends have been discouraged by the extremes to which this sort of thing can go.
To change the subject somewhat, that's my problem with the ADL under Abraham Foxman; they aren't looking for their current enemies in the right places.