Homosexuality is like smokers, alcoholics, drug addicts, certain sexual fetishes, or other unhealthy behavior. The people who engage in these behaviors either think that what they do is perfectly normal, or they have no way to stop doing what they are doing. Because homosexual activity is so emotionally based, it requires more intensive therapy to change the behavior.
Regarding the APA, Time Magazine, back in the early 1970s, reported on the gay activists demonstrating outside of the APA's meeting, which got violent. It was through threats, not any scientific research, which got the APA to take the behavior off of its abnormal list. Look at all of the so-called studies in recent years - none of them state they show conclusively that homosexuality is genetic, and none of the favorable ones have come even close to being duplicated by other researchers. But you wouldn't know that from the media and the activists.
Without getting too much into Catholic theology regarding human sexuality, all of our body parts perform basic biological functions. The human behind is used for removing waste from our bodies. It is not built for intercourse, and is greatly harmed by those who engage in placing things there. Other body parts give pleasure as well, but, again, that's not allowed, either (Catholic theology coming into play). How anyone could say homosexual activity is anything but abnormal, I'll never know.