You’re conflating two different questions into one. ‘Is there a time to punch a Nazi,’ and ‘If we study Nazis, can we figure out how to stop people from turning into Nazis that subsequently require punching.’ I’m personally of the opinion that the answer to both is yes. There is absolutely a point in understanding evil because, as we are having so comprehensively demonstrated, Nazis are not a one-time problem. Letting things get to the stage where punching is required has consequences.