The way I see it, whether or not you think you are these guys:
you're playing a
simulation of the blowing up of these guys:
with the overall objective of helping this guy:
beat these guys:
Maybe they weren't all nazis, but they weren't many Marco Ramiuses either. Did any u-boats actually defect before 1945? Anyway, if taking part in the above bothers you, that is okay. It doesn't bother me - submarines are too cool.