Obviously anything to do with Nazis or the Holocaust triggers this reaction faster and more severely, but it can happen with any subject. Every argument of "Currently A is happening. When A happened in {time/place} it led to B and then C, and we all agree B and C are really bad" will be met with "How dare you compare yourself to {time/place}! B and C aren't happening now and will never happen again" (with no explanation for what will prevent B and C from happening).
You and I may be moderates, but you have to agree, there definitely are more than enough people who would support mob justice (to take a mild example, the attacks on Google's buses recently... the entire situation seems like a powder keg)
