Upvote:4
As far as I know, the Catholic Church hasn't made any statement about the origins of h*m*sexuality.
The best way to understand this perspective of h*m*sexuality as a "disorder" is as a mental or emotional disorder.
To be clear, the Catholic Church hasn't actually called it that, but that is similar to how it has been described, both in your quoted material and elsewhere.
There are a lot of disorders: anorexia, OCD, schizophrenia, alchoholism, p**nography addiction, bipolar disorder, etc. Identifying a single "source" would be complex and difficult. Genetics, environment, and individual choices all contribute. But regardless of the origin, these are all out of place, and we should see help from therapists, family, friends, and Christ to overcome them.
As for intrinsic, Merriam-Webster defines it as "belonging to the essential nature or constitution of a thing". Thus, intrinsically disordered means inherently incorrect. Homosexuality is not conditionally or occasionally appropriate; it is incorrect in and of itself.
Your quote also says that h*m*sexual tendencies are objectively disordered, which means it is wrong even from an impartial viewpoint. Put those together, and Catholicism sees h*m*sexuality as fundamentally and clearly out of place.