2016 Postmortem

I think part of what you call "racial insensitivity" was simply justified resentment at the way anti-oppression politics(a set of issues Bernie was always just as committed to as HRC) was manipulated to try to make young progressives feel that they owed it to people of color to support the less-progressive candidate(as well as the despicable claims that the Sanders campaign didn't try to win POC support-or in some versions, didn't even WANT POC support, and that whole Sanders project was a "whites-only" thing) or that the Sanders campaign wanted the party to treat social justice issues as LESS important than economic justice issues(they wanted BOTH sets of issues given equal priority), or that economic justice would somehow only benefit white people.

There was NO difference between Bernie and HRC on social justice/anti-racism/anti-oppression issues, Bernie never deserved to be accused of not caring about those issues, and since Bernie will never run for president again, there's not any good reason to keep attacking with primary talking points on that issue.