Matt Abott received comments from three priests the forthcoming document barring gays from the seminary. One of them in particular gives a very clear exposition of what it is about homosexuality that makes it incompatible with the priesthood (or at least one of the reasons). Father Burns Seeley of the Society of St. John Cantius says:
The key point seems to be that homosexuals possess ‘a serious personality disorder which detracts from their ability to serve as ministers.’ I take this to mean that they are incapable of perceiving human nature as God as created it, consisting of male and female persons meant for mutual attraction, complementarity, and, God-willing, marriage and children.
Instead, they see members of their own gender as mutually attractive in a sexual sense. They do not see females as such. In other words, they do not see or experience objective reality. Since this is so, it follows that homosexual priests possess a serious handicap which makes it extremely difficult, if not impossible, to serve well as our Lord’s faithful ordained ministers.