"people do not change 'orientation', they change behavior, maybe."
That's the crux of the matter that ought to be considered by those who believe homosexuals can (and/or should) be reformed.
Forgive the simplistic and aruably idiotic-on-some-level analogy, but I think it not altogether inappropriate:
If someone loves chocolate ice cream, and hates vanilla, you *may* be able to reverse that on some level, but only with brainwashing techniques, never with anything honest or straight-forward, nor with pure "logic" or argumentation. Otherwise, if you're not fully successful, but beat it into their heads that chocolate is of the devil, and vanilla is the way and the light, they may start eating vanilla, though it almost makes them physically ill, but they're going against their innate, low-level desires, only having temporarily repressed them (they're sure as hell not going to yell "JESUS!" when they consumate their union with vanilla). They'll still love if not the taste, at least the memory of the chocolate, and feel the associated guilt of loving something evil. The guilt alone of being themselves evil for so strongly wanting that which is evil may be enough to destroy them. If not, it's only a matter of time before they start sneaking off to Baskin Robins for illicit rendezvous, or, at the very least, experimenting by topping vanilla ice cream with Hershey's syrup.
I think my analogy took on a life of it's own there, but I hope I made a point.