I get there's a huge difference with sex drives, it causes serious problems in relationships. But even a low sex drive does not mean a non existent one. Even asexual people are not always celibate.

My grandfather was in seminary, they're definitely not all asexual people at that. Maybe some are and it would make more sense for them, but plenty of priests I assume have normal sex drives.

Due to the nature of male and female sexuality there will be a LOT of men that just don't get to breed for various reasons

Incels? That's a problem with the incel, any guy that wants to get laid can.

non sexually reproducing men useful for the community

There's a lot of contributions people can make besides having offspring. I'm specifically talking about fucking though, even if it's just fucking for fun. That's a normal drive for most people, although it isn't universal.