If Germany says, "Oops. It won't happen again," they should be eyed with suspicion.
Actually, I'd lean the other way. Having wrestled with the aftermath of such a recently vile history, my experience of Germans is that in general they are incredibly aware of the dangers of seductively stirring, jingoistic, right wing rhetoric. They are proud to have a criminal offence of holocaust denial, for example.
Other nations don't have that cautionary experience - witness the poll numbers for Trump, which just get higher, the more racist, reactionary and downright fascist he gets. I reckon that in today's Germany, they'd have locked him up by now.
Could there be any greater conceit, than for someone to believe that the universe has to be simple enough for them to be able to understand it ?