If one genuinely believes in a religion, then being a priest is presumably one of the most beneficial careers imaginable. I wouldn't preclude somebody being both a homosexual and a genuine believer. One could even view it as a means of trying to atone, from their perspective.

This could be the same reason you so often see things like male sex predators seem overrepresented in e.g. feminist groups. The knee-jerk cynical view is that they're just their to prey on the women, but a more empathetic view might be that they are genuinely trying to atone for their inclining.

But in the end, we all are who we are.