The time frame cited was the late 1960s. The article doesn't cite it, but the association between that and grade inflation had nothing to do with desegregation

The time frame cited was the late 1960s. The article doesn't cite it, but the association between that and grade inflation had nothing to do with desegregation and everything to do with the fact that students who flunked out lost their Vietnam draft deferment. So sympathetic faculty and graduate students handed out good enough grades that they wouldn't flunk out. This reversed temporarily after the war ended, but then a long term trend began not long after. See http://www.gradeinflation.com/ http://www.gradeinflation.com/ for more detail on that trend.