I could imagine that Germans have already grown tired of all those Nazi comparisons. Just like French grow tired of those stupid surrender jokes. It's been sixty years, almost 4 generations. Seriously, there is no responsibility left for what their ancestors did. I've been to Germany a couple of times, they are fine people.
Spock's comment "You should make a very convincing Nazi" is pretty much careless and thoughtless, and something Spock wouldn't say.