I don't know if it is about racism. I think it's normal to become defensive when accused. If I say "your ML model is garbage" I am sure they will (maybe, if I am high-profile too) provide an explanation on why or why not.
I don't think the researcher was being defensive just because it was about racism.
Many see these systems as a way to implement stop-and-frisk (quite racist outcomes) and worse across the country using AI/ML as cover. The higher error rate amongst darker skin people gives LE a new excuse to harass innocent historically disenfranchised people.
I expect this tech will be widely used long before the accuracy problem that affects ~60% of the global population is fixed.