100% agree. One concern I have is that in a real sense the whole rest of America also benefited from the forced labor camps of the south. The factories in the north, which built wealth for northern industrialists, depended on cheap cotton from the south. We in the north like to wash our hands of slavery and point to slave owners as "the" bad people, but it was a whole interconnected economy - sort of like how our whole economy depends on cheap goods from places where labor is exploited and environmental standards are ignored.
So yes. Having a destination wedding at a concentration camp is definitely "off." But only because of the stark contrasts between the house of the owners and the lodgings of the enslaved people. Until we recognize our whole history, everything everywhere should feel off in that way. I suppose the same off-ness could be felt by white people at Mount Rushmore, realizing that those are sacred mountains to the Lakota.