True, that some people struggle with that particular attraction as sin, however, according to Romans 1, it does indicate a depravity of human nature that goes beyond the ordinary.
The problem is, if it were only an orientation, or rather a temptation, then there would be no need for anyone to know about it.
Unfortunately, what with the prevalence of gay priests, obviously it is not remaining something unknown.
Another problem I see with it, is that by acknowledging it and not doing anything about it, it tends to foster an acceptance of it, which will eventually erode the stigma, or sense of sinfulness, about it.
I completely agree with your view on temptation not being sin. It only becomes sin when we entertain and then engage in it, even if only on a mental level. Sin begins in the heart often long before it manifests in the actions.
???
1 Corinthians 10:13
There hath no temptation taken hold of you but such as is common to man...
The Catechism says that the homosexual orientation, in itself, is objectively disordered. It is not sinful in itself, but it is something which inclines one toward sin.
An analogy bight be fetal alcohol disorder, or prenatal cocaine addiction, for which the child is not to be blamed, but which is going to make him psychologically vulnerable in certain areas for the rest of his life.
If he is aware of this, he has the moral obligation to avoid situations of temptation, and to strengthen his resistance to sin, by the grace of God.
The same may be true of some tempermental factors. Some people are especially inclined to childish silliness, some to melancholia; some people have a hot temper and a short fuse; others err on the other side, by being too softly tolerant, unable to rouse to anger even to fight injustice.
I think knowing one's own temperament --- and tuning always to the mercy of God --- can help one avoid habitual sins.