You put more emphasis on Hitler, over other dictators who genocided mass numbers of people, because you identify more with Jewish people's plights than those of the others. The Slavic or Cambodian people, and the atrocities directed at them, feel more distant because they don't have much of a voice in the international stage. There are no movies made about them, no stories written.
I do not say that as a way of taking anything away from the Holocaust, but just as a matter of fact. We here in the West don't give much of a shit about the millions of Chinese dead under Japanese occupation. If somebody wants to play at being Emperor Hirohito, nobody'll give a fuck, even in America, even though him and the Japanese bombed Pearl Harbor and directly attacked America, whereas the Nazis did not.
As for people doing Nazi salutes, couldn't care less what some fringe groups consisting of about two dozen individuals do. Whatever floats their boat. As I said, Nazi LARPing has become a thing because it is the "counter-cultural" thing to do.
The more you get disgusted by it, the more you will see it done by people who despise mainstream culture anyway.