press.vatican.va
Gen 1-3 tells us
1. What a woman is
2. What a man is
3. What marriage is
4. Our obligation as God's divine direct creation
Ex 20:11 confirms that all that is literal -- and it does it in the form of legal code.
The church cannot oppose the Word of God - so then the statement that the church cannot bless what God calls abomination in Lev 18 is logical
The longer way to say that -- from the link in the OP
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Blessings belong to the category of the
sacramentals, whereby the Church “calls us to praise God, encourages us to implore his protection, and exhorts us to seek his mercy by our holiness of life”[4]. In addition, they “have been established as a kind of imitation of the sacraments, blessings are signs above all of spiritual effects that are achieved through the Church’s intercession”[5].
Consequently, in order to conform with the nature of sacramentals,
when a blessing is invoked on particular human relationships, in addition to the right intention of those who participate,
it is necessary that what is blessed be objectively and positively ordered to receive and express grace,
according to the designs of God inscribed in creation, and fully revealed by Christ the Lord. Therefore, only those realities which are in themselves ordered to serve those ends are congruent with the essence of the blessing imparted by the Church.
For this reason,
it is not licit to impart a blessing on relationships, or partnerships, even stable, that involve sexual activity
outside of marriage (i.e., outside the indissoluble union of a man and a woman open in itself to the transmission of life),
as is the case of the unions between persons of the same sex[6].
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Though the civil government of China should "rewrite the Bible" even though such is condemned in the Bible
Though the civil government of the US should "redefine marriage" and all moral law in God's word that relates to it
It is a violation of separation between church and state - to have the state rewrite the Bible or to have it redefine Bible morality