You seem to be contradicting yourself.  On the one hand, you state that the "scandal which is given to the church by sexually active priests (gay or straight) is devastating .... and clearly neither gay nor straight clergy have a monopoly in this field."  Then, you say that the bar is reasonable, because it limits "opportunities for scandal", thereby implying  that openly gay priests are more likely to give scandal.  The latter suggestion is highly offensive and quite frankly, untrue.
I would suggest that they simply bar males from the priesthood, since it has been shown that it was males who have abused children and who have caused scandal through their sexual dalliances.