My mother did the same thing. My father and sister both demand dark meat. Thats it, nothing else will be tollerated. BUT...... Since I have started smoking again, both have decided that they can eat white meat, as long as I cooked it. Even the care giver, exact same thing. I am starting to see it as a trend. Most folks eat dark meat because its generally less dry when over cooked.My mother always overcooked her turkeys, as did her mother. The white meat tasted dry and chalky, requiring lots of gravy. I suspect it had something to do with the way they were taught to ensure no one got food poisoning.
Her mom loves it moist. There is a funny story when she was in grade school she said grandma your turkey was good. It was dry. Her mom had to tell her that us usually an insult- dry turkey. She just prefers it that way.