Puzzling isn’t it, why would someone with hearing loss say that?
One reason is called recruitment, and it’s a feature of sensory nerve hearing loss.
Do you remember the hair cells in the cochlea? They are grouped into bands and each of those bands deals with different frequencies. When one of the hairs stops working then its band needs to find a replacement and so the band recruits some cells from the next door band. If there aren’t enough working hair cells in those bands to recruit then they move along another band, and just keep recruiting from the adjacent frequencies until they have a full set. Sometimes one hair cell can be recruited into several different bands.
This means that the hair cells are working several jobs at once. If one cell in a band sends a signal then they all do, so several bands could all be sending signals at the same time. So that sound can appear to be twice as loud, or three times, or four times as loud, maybe more – by a factor of how many times the signal is sent.
For some people when a sound to be loud enough for them to hear it it is too loud for them to bear.
Another result of having several frequency bands sending signals for one frequency is that the sounds become blurred, with little distinction between the frequencies. This makes it hard to distinguish words. So what you hear is often unintelligible noise. Gibberish.
I think the nearest a hearing person would get to this effect is in the commercial breaks on TV, or in the movies. The sound is altered so that it bombards you with all the frequencies and so it seems louder.
So please, please don’t shout. Just repeat yourself a little more slowly and more clearly. If that doesn’t wok then rephrase, or write it down.
When I get home the first thing I do it to take my hearing aids out. If my ears could sigh then that’s when they would do it, so please please don’t shout in my hearing aids.
It’s also worth mentioning that shouting distorts the face and makes it hard to lip read. It also makes faces look very aggresive too.