I think you shouldn’t just prejudge and categorize someone without knowing their thought process. Just because someone knocks on the door after the store is closed, it doesn’t mean they’re a “flaming asshole”. E.g. I also also knocked at a store at such a point because I lost my wallet inside the store. (Luckily, the people there were really nice and opened it so I could search for it.) Most customers are just… people. Maybe that’s a cultural difference (I’m not from the US), but as I customer, I always see a store worker as a human and engage respectfully, and at least most people I know do the same. Doing something like pushing them to do something they can’t do is awful behaviour, but I don’t see why you would expect that from a customer or think every customer is an asshole like that.

And about the original comment, I thought they weren’t aware that the store is closed and just confused, and then it doesn’t hurt to clarify. Of course if they wanted to be served after hours, this would be pretty ridiculous.

(And I personally also had situations where I was confused because a store closed an hour earlier than it said on the door and online.)