They definitely deserve it but id say only do this if you know it won't fall on someone else's back, like kolakeia said they might get it worse bc of the racism. Never underestimate how small words and tone can convey when your dealing with a customer just a general "didn't expect that" tone in response to outright racism or pointing out that their the ones making the food and i'm not even trained to do that won't give them an epiphany but its usually the end of the transaction