As for the Holocaust and Trail of Tears things, there is a difference. She isn't trying to reenact something where people were treated horribly as the main event. She was trying to have a themed wedding. Slavery wasn't itself being reenacted. And it wasn't being used to glorify slavery. Plus, it would be wrong to have a German 1940s wedding/party theme that included guests/staff with stars or other identifying emblems on them, but it would be still be a case of bad judgement in most cases, unless some other evidence comes up to state otherwise.
I think that most of the backlash came from the media information, which is still not enough. Look, even you went immediately to the "separate bathrooms" thing, despite that not being proven or supported as true by anyone else so far.
I just don't support firing someone just because they have done/said things in their past. They are free to do it, but it doesn't change my view on it. And I feel it is especially wrong to do it when we look at how many others have been treated with so much less animosity for doing things that should have been a hell of a lot worse. It appears more like "jumping on the bandwagon", than sticking with principles.
On a side note to this, I found it interesting that I can still buy her products at the NEX. I saw them just this past week.