Sexual preferrence ceases to be relevant for those who voluntarily forgo sexuality. If the priesthood forbade motorcycles, a priest might still like motorcycles, but he would cease to be a biker.
Heterosexual celibates cease to be attracted to women?
I don't think that's true at all. In fact, I know it's not.
A "preference" is a taste among equally valid choices, such as beef verses chicken for dinner. Or red verse blue in buying a car.
Homosexuality is a mental disorder. It can no more be called a preference than people who talk to themselves or people who maim themselves calling those behaviors preferences.