Officially AC employees are always supposed to be courteous and graceful to their customers, co-workers, etc. Even if they don't go to the right counter, board in the right zone, etc.

Unofficially....

Truth be told, many front-line AC employees are severely over-worked, stressed out, and suffer from poor mental health as a result. So they over-react.

You could write the company. They'll probably send you a discount code in response. But that aside, I'm not sure what other remedy you have other than to vote with your wallet (is the competition really better though??), or put up with it.