I’m another one who doesn’t understand this observation. If you have a pax in need of medical attention for whatever reason the priority for the crew will be dealing with that passenger, and that might mean not expediting disembarkation, perhaps asking everyone to stay seated, and also perhaps a low priority may be placed sparing the sensitivities of those leaving the aircraft.
FWIW there are airports where disembarkation via rear steps isn’t allowed, and there can be medical problems on arriving flights on many aircraft where rear steps aren’t an option or aren’t going to help. Fundamentally It is something for the crew to manage on the day...