Someone who thinks there's a moral failure in refusing to stick together with your in-group under adversity should remember that this instinct could have put you on the wrong side of the Holocaust

From a strictly utilitarian standpoint, if one had a strong commitment to the common good, but uncommonly little knee-jerk reaction or natural empathy, would it have made more sense to passively tolerate the Holocaust/offer only safe resistance, and live to affect the post-war world, where there could be more one could do for oneself/humanity?

Or make a stand and give your all to saving as many as possible, feeling plenty of moral gratification, and trying to go out in a blaze of glory when They came for you, which could also make you an inspiring example in, say, half a century?

I used to hold the former completely unacceptable after being strongly influenced by Hannah Arendt's Origins of Totalitarianism (a great read, highly recommended) and her notion of "Radical evil" (somewhat deontologically loaded), but I have yet to attempt a rationalist evaluation of what I've read.