Figures it’s trending on twitter.
But in seriousness, looking at the body language, it’s really hard to tell when you can’t see facial expressions. The employee could have been spitefully saying “no” with that hand gesture (and if they were, shame on them), or they could have just been waving “hi” not knowing the girls wanted a high-five. I dunno, but I don’t want to just jump on the “THIS WAS RACISM!!!!!!” bandwagon because I feel it’s too easy to jump on that, at least not until more info comes out.
EDIT: Okay, now I see they’re shaking their head. So that does add something. However, I was also reading that it’s possible the employee thought the girls wanted a hug and said no in response. Again I want to see more info to this story before determining if it was racially motivated.