I’d be very surprised if rudeness is company policy(there’s probably some really weird veblen good where an adversarial buying experience is part of the appeal; but I don’t think this one is one of them); but it seems much more plausible that an employee did something that a customer perceived as rude (whether on reasonable grounds or with the assistance of either loose or overtightened screws).
Even fairly brutal labor discipline isn’t necessarily enough to keep the people stuck working retail smiling; and one can only suspect that people buying stuff to signal status and flex on the poors are particularly charming to work with.
