Last week my Prog-Troll FB Friend plopped the story about Trump's business having been sued by the Feds for racial discrimination in renting housing (the story was true, sort of; the suit was filed in 1973 and Trump's business settled; what the Prog-Troll's story omitted was that the Feds' evidence was gathered in 1972 and earlier, before Donald Trump took over his father's business). When some one pointed out to him the absurdity of a 43-year-old lawsuit being the evidence of present racism, my Prog-Troll FB Friend responded with, "Once a racist, always a racist." I responded with Wikipedia quotes indicating that both Byrd and Hugo Black had "apologized" for their KKK involvement, and then asked him whether their apologies were believable.
BTW, Byrd was not just an ordinary Klansman. Byrd started his local KKK chapter, was its Kleagle (recruiter, possibly a paid position), and became the chapter's Exalted Cyclops (head of the chapter). IOW, Byrd didn't join the KKK for business/career reasons! Byrd fully BELIEVED and advocated the Klan's racist sewage!
I do believe people can realize when they've been wrong and change. Hypothetically, I could believe it of Byrd, but DU-member "former9thward" cited evidence to the contrary. Byrd may have morphed away from cross burnings to, "Negros are OK, as long as they aren't around me," but that's still racism. Similarly, I could believe Hugo Black did change, I just don't know and it doesn't much matter to me one way or the other.