Your assumption that the clergy are not supposed to have any sexual orientation is wrong.
They are supposed to be celibate. But they are also supposed to be healthy mature men, and that includes having a healthy, mature and well-integrated sexuality. They are not supposed to be asexual; just celibate.
Which raises the question, can a healthy, mature and well-integrated sexuality be consistent with a homosexual orientation?
There’s a strong view - not an unquestioned view by any means, but a strong view - in the Catholic tradition that the answer is, basically, no. Homosexuality is not oriented towards the good of procreation; therefore it is in some (important) sense deficient. On this view, we all ought to be heterosexual; those of us who aren’t are, in some sense, “broken”. (Just to put that in context, we’re all “broken” in Catholic thinking; gay people would be “broken” in this particular way, but not uniquely “broken” compared to the rest of humanity.)
The question is, is this particular “brokenness” something which should be a bar to a man becoming a priest? Mostly the church has tried to fudge this issue; on the one hand, you have your purists and puritans who would be horrified if the answer was no, it shouldn’t; on the other hand you have those who would be horrified if the answer was yes, it should; on the third hand you have the practical reality that, if you succeed in barring all gay candidates, you have a lot fewer priests; on the fourth hand you have the practical reality that, in an institution with a well-established don’t-ask don’t tell culture, how can you exclude all gay candidates? And if you can’t enforce such a rule, what is the point of having it?
But relatively recently, Pope Benedict did come down on one side of this question; men with “deep-seated homosexual tendencies” should not be ordained. General delight in certain quarters; general dismay in others. And the subtext behind all these questions to Pope Francis is, does he agree with Benny’s position? Is he going to change the way the position is stated? Is he going to change the way it’s implemented? Is he going to support it, publicly reverse it, quietly bury it, something else? And the existence of a widely-spoken-of “gay lobby” within the Vatican provides journalists an opportunity for raising the issue.