Sounds like it was a bad joke towards an instructor who treated them like a Nazi. You know, sort of like your PM being caught in blackface several times. Is it really a good move to fire an entire class of cadets because they made a bad joke toward an instructor? How many weeks training times how many officers? Get to the bottom of this. If they are Neo-Nazis than I say fire them. If it was just a bad joke like some sanctimonious left wing liberal who constantly turns up wearing black face, then you put a letter in their file, make them apologize and move on.
A local high school was allowed to start a communist club on school grounds and the kids aren't joking.