Alternate history is impossible to prove, and to your point, my history is just as fuzzy if not fuzzier; however, I do remember the reverence RFK had for MLK when announcing his assassination.

I don't know that the Civil Rights Act passes in this timeline, at least not at the exact moment, but maybe it does? However, you get to avoid Vietnam. Maybe it's not helpful pondering these sorts of things, but is trading the Civil Rights Act for Vietnam a good deal, net benefit for humanity wise?