Hitler and Nazis are evil, so they are a convenient shortcut for describing evil
Hitler was a bad, bad person. His rise was also facillitated by a lot of other bad, bad people, notably the Nazis. It must be admitted, as well, that he stands as a stunning example of the dangers of moral bystanding in the face of evil. It is with good reason that he is often identified as a touchstone of human evil. For this reason, using Hitler in a work is an easy and straightforward way to buy some evil cachet. Hitler + X is a pretty simple formula, too, for fantasy works, resulting in such tropes as Stupid Jetpack Hitler and Ghostapo. Hitler's name and the word Nazi is also a simple approach to pejorative. This can lead to Hitler Ate Sugar, and is the pathway to Godwin's Law and all its correlaries and variants. Visually, this trope is accomplished by Putting on the Reich. The dire reputation of Hitler and his Nazis also makes them tempting targets for lampoon, mockery, and shock humor. With all the above in mind, this makes Hitler and Nazis a ripe target for naming tropes after Hitler or Nazis. There are good reasons to reference Hitler or Nazis in trope names. One such reason would be that the trope actually relates centrally to Hitler, Nazis, or a phenomenon associated with them. Bad reasons include... well, most reasons that are not that.