We did not set out to make it into this whole thing.

I'm going to have to give you the benefit of the doubt on that one. But assuming you didn't, that you just screwed up, here's the catch -- ignorance/"I didn't think it would be a big thing" is only an excuse so far as you are willing to acknowledge your mistakes when they're pointed out to you, and work to change what you can. That does not mean throwing up your hands and saying "well, sorry if you're offended, but them's the breaks", it means saying "we're sorry we've offended people and that this got out of hand", and then changing the blessed name.

From what I can tell, you're trying to have it both ways here -- you want to be thought of as respectful, but you also want to keep the edgy (no pun intended) name. You cannot do both. You can, perhaps (if you're a far more skilled writer than I) touch on the parallels between Grindelwald and Hitler without people getting het up over it; as I say, Rowling's done as much in canon. But you cannot come right out, explicitly state that a fictional movement in a children's fantasy series is equivalent to the systematic torture and slaughter of millions of people and simultaneously be considered respectful. It's exploitative and it's beyond disrespectful. If you want to keep the name, go for it, but know that at this point, when people have said you've screwed up, you have no room to complain that you're being accused of disrespect. You've made your bed, and now you have to lie in it.

I've got myself into wankstorms before. It's embarrassing and infuriating. But here's the really unpleasant part -- upon reflection, a few weeks/months down the line, everyone who was saying I was acting like an idiot was pretty much right. I could be mad at them for being rude to me, but I couldn't deny that they were right about my behavior being stupid, even if I'm not stupid. I don't think you're a bad person; I don't think you're endorsing the Holocaust. I do think that if this many people are telling you that, however blurry the lines might be, you've crossed them, then you have to acknowledge that maybe they're right.