I’ve heard it explained that “hey” used to be more of an urgent way to get someone’s attention, rather than a casual “hello” like it is now, so it sounded rude to some older folks.
I’ve heard it explained that “hey” used to be more of an urgent way to get someone’s attention, rather than a casual “hello” like it is now, so it sounded rude to some older folks.
It could also have been just that - an old joke that everyone liked responding with when they had the chance.
That is how I always perceived it. I can’t even imagine someone saying that with a straight face as a correcting rebuke.