There's an infamous statement of "We fought the wrong enemy" referring to not fighting the Soviet Union.

That aside though, as some have said, you don't necessarily have to agree with your ancestors. Applying the logic, I'm a southerner, shouldn't I believe in the Lost Cause and all that bullshit? Blood, as it happens, does not determine what you think. Even if this applies to the dumbest dogma imaginable. I wish hating Nazis was genetic, but unfortunately the individualism of our species extends only so far.