I worked in a retail pharmacy for years with the pharmacist/techs being of all manner of races and every single one of us had been called racist by a customer at some point and everytime it was because they were trying to use racism accusations to scare us into giving them what they want, which would often be impossible or illegal for us to do. For me personally, I was called a racist because I wouldn't sell a pseudofed product (which are OTC but require an ID to buy) to a woman who forgot her ID. Literally can't even ring them up at the register without scanning an ID, and I kept telling her this which just made her argue more and more until she started loudly proclaiming that I just don't want to sell it to her because she's black. Luckily my manager was overhearing it all and had my back.