I think that one of the biggest problems the church has is that the priesthood is exactly the kind of job that would appeal to a guilt ridden homosexual. They're not attracted to women, so giving up a family life isn't the same sacrifice to them that it would be to a straight man and being sincere Catholics, they are probably very ashamed of their homosexual inclinations and vows of chastity and a chance to work directly for God probably seem like an excellent way to atone for their sins. A great many of them are probably actually able to control their proclivities through their religious devotion and of course the majority of priests are not gay at all, but if you've got a sizable enough minority that are then there are bound to be problems.
It's kind of like the way some bullies are attracted to police work and nutcases to psychiatry. Good jobs often are a magnet for bad apples.