States rights is hogwash. We’ve gone through this as a country already.
State rights is fundamental to the country. Yes, you provided a bad example of it, a misuse of it, but that was the world at the time, and it was not unique to the United States. There's a lot of brutality in human history, medieval people were downright barbaric. Hopefully we learn from our mistakes.
Anyway, as divided as the country is, I think states rights are maybe the only way we're going to be able to live together. This way, people in some states can live they way they want, and people in other states can live the way they want. If it's a free for all for who can grab the Federal authority and then use that to browbeat everyone else into doing everything their way, that's going to get really ugly.