I'm not American but I've been reading up on American history. This is reminiscent of the propaganda that said slavery taught black people to be hardworking and discouraged laziness, which was in line with Christian values at the time. Is that correct?
It sounds about right. (That it lines up with the propaganda, I mean. Not the propaganda itself.) Republicans hate the truth of history that white people owned black people as slaves and treated them horribly. They don't hate it because it was a travesty, though. They hate it because they are racist and see teaching proper history as an attempt to make them "feel bad for being white."
So they push back with their own version of history where all slave owners were kind hearted fellows who helped those poor black folks that didn't have any jobs. Republicans want to twist history to make heroes out of the white slave owners.