Yes, a leader can be corrupt and dictatorial, and yes, they can strong-arm many people. To somebody with strong morals and heavily deontological beliefs, they can look at that leader and say "How could anyone support such a person?". The answer is to look at a concept like Maslow's hierarchy of needs [1] and realize that the supporters are likely pursuing an entirely different stage of needs than you. When your kids are hungry and you have to work from sun-up until sun-down to keep the family fed, and somebody makes it easier for you and your family to survive and maybe even have extra money at the end of the week, none of the moral ideologies against corruption or dictatorship really matter to you. That's why Russians give Putin such a high approval rating; they don't deny that he's corrupt, they just don't care, because their lives have improved.
The same can be said of hopeful Trump supporters to a lesser extent, in fact, and linked is a fantastic analysis on that topic (the most fair and analytical one I've read) [2].
My point is: the above poster's mother wasn't apologizing for Nazis. She was likely saying that, as far as she could tell at that point in time, similar to my Russian family, her family's life had improved. I don't see how that becomes false in light of future events.
[1] https://en.wikipedia.org/wiki/Maslow%27s_hierarchy_of_needs
[2] http://inference-review.com/article/trump-and-the-trumpists
Nazis being evil from the start isn’t a retcon. Just look at their internal party purges, or how the Enabling Act got passed.