Do you think he would not apply the same reasoning to any pair of people practicing the same behavior? This is a letter about movements to make sexuality a protected legal class, with specific focus on homosexuality. It is not coincidental that a letter about those things also has specific focus on homosexuality. There are other statements from the Vatican about other related topics.
He never
did apply the same reasoning to heterosexuality, and there's literally zero reason to think he would. He only ever used this language in connection to homosexuality, so if you're opining that he felt the same way about heterosexuality, you have pure speculation to go on.
But while we're here: the "behaviour" in question here is... having a romantic relationship and sex, that doesn't lead to procreation. Do you believe that's an "intrinsic moral evil"? Not the recognition of it with additional rights or marriage, but merely the tendency to want it?
So anyone infertile, anyone past menopause, anyone who doesn't want kids-- if they form a relationship or have sex, that's an "intrinsic evil"?
The Catholic Church helps people get housing, which some resources specifically for married people. Married by Catholic standards. The Catholic Church hires lots of people, and many of them, particularly teachers, are paid to represent the Catholic faith. This isn't "gay people should all be jobless and homeless", this is "we can't be neutral to this with our own practices."
So, discrimination against gay people in housing and work is A-OK in your view. Just say that.
I just need to keep the contempt with which you hold me in mind, next time we have a debate and you act outwardly respectful. Gotta keep in mind you'd be happy to deny me job prospects or housing because of what I am.