Do you not know what analogies or metaphors are? Like, you do know that the person you replied to wasn't comparing either of these men to Hitler or Himmler, right?
To exaggerate and make a point? To rile people up and ruffle some feathers? The comparison isn't between the two of them and the two Nazis, the comparison is between the two of them.
Yeah, the implication is that their bad or evil, but I don't really see it as comparing them to the Nazis. They just exaggerated for effect and used the most extreme example of "evil" they could think of to make a point.