First, two points:
- The belief that God is a Trinity is orthodox.
- Claiming that a non-Trinitarian “god” (whether the Arian god, or the Sabellian god, or any other) is the true God is heresy.
By those two points, how is this statement as written not objectively heretical?
The Church regards with esteem also the Moslems. They adore the one God, living and subsisting in Himself; merciful and all-powerful, the Creator of heaven and earth, who has spoken to men; they take pains to submit wholeheartedly to even his inscrutable decrees, just as Abraham, with whom the faith of Islam takes pleasure in linking itself, submitted to God.
(Vatican II, Nostra Aetate, Section 3)
The god that Muslims adore (Allah) is not the Holy Trinity - how on earth does it say that he is “merciful and all-powerful, the Creator of heaven and earth” ?!
Please note: I’m asking you to respond to the exact words and phrase here - this document is the focus of this thread, not things written elsewhere.