This says much about respect and social competence in this society when the first instinct is to mock and abuse someone with different priorities than yours.

When they are that rude and stupid they have it coming

You mean “rude” in asking for a cashier? Not sure I understand

They didn’t ask.

service is not something the client has to ask for but something the vendor provides. Just like you hold a door open for someone entering behind you, you provide that service, unasked.