I don't know, from what little I've read it seems like something random... although it doesn't make sense
In fact, if it were a racist incident, it's a good example of where such stupidity can lead
Discussion
Apparently not caring about skin color is racist.
It's known as color blindness.
The human being is a biopsychosocial being, attributing murderous behavior or a higher probability with respect to another individual based only on their skin color is a mistake... however, it is normal in human nature to base stereotypes to discriminate in any situation, in conclusion: it can be a red flag although of very little value on its own