Why not blame the Thais who are being racist, given the actual very low number of issues there are with foreigners in Thailand?
There's literally zero logical reason to think that a random foreigner in your store is there to steal, simply because they are foreign.
And yes, if someone believes that seeing an occasional "drunken foreigner does something stupid" article means it's ok to assume that all foreigners are thieves, they're probably a racist too.