So, I have significant hearing loss in both ears to the extent that even with hearing aids I generally have to tell people I have hearing loss so they slow down/repeat themselves. Invariably some smartass replies "what?" and pretends they didn't hear me.
I've had this with people I know very well (hearing loss not from birth) and with new people as well. I think it's ignorant, rude and quite frankly just not on. I don't see why it's widely accepted as a funny thing to do.
However, whenever I make it clear that I'm not amused I get the reaction of "oh, it is funny, take a joke etc etc".
AIBU? I hear(!) it so often that even if it was funny, it wouldn't be by now.