I'm not 100% sure why they wanted to see her ID -- that's not improper, but I always think that's kind of authoritarian. But it has nothing to do with her race.
Exactly.
That department has a 100% no exceptions ask for ID policy. This avoids the usual race baiting claims that “YOU ONLY ID PEOPLE WHO LOOK BLACK/HISPANIC/NONWHITE”.
This whole incident is a case study in why all police interactions should be recorded - this may have just saved these cops’ careers and hopefully torpedoed this woman’s career in academia.
The policemen asked her for ID when she started to establish the case that she was being stopped because she was black. They did this for the record in case she started to put forth the claim I suspect. Before that, they simply suggested she walk on the side of the road facing traffic.