So the suggestion is that if Person A makes a generic comparison between Hitler and someone else (regardless of what aspects of the two people are being compared), then Person B will no longer be shocked by Nazism or the Holocaust? I disagree. If a comparison can be made then why not make it? It's not disrespectful to anyone other than the person who is being compared to Hitler. And it depends what the comparison is. If someone was to say 'Trump did x and that was as bad as the Holocaust', then obviously that would be incredibly disrespectful, but if it's a comparison of a particular policy/personality trait (I don't know exactly what the comparison is that has led to this thread) and the comparison exists legitimately, or there is an argument to be had for it, then I think it's fine. Calling it 'Hate Speech' is a bit much to be honest
I remember when I was at school we had a teacher that everyone called 'Little Hitler'. It wasn't a comment on Nazism, it was just a silly meaningless insult aimed at the teacher for being a ****.