It turned away the wrath of God so that He could
A Catholic is always going to have a lot of problems that are predicated on the idea that something has to happen so that God "can" anything.
To the Catholic mind it is axiomatic: God is God, and therefore He CAN do anything. Whether he WILL or not is purely a matter of his own free will.
So in talking with Catholics, if one wants to get far along in the presentation of a view, one should try to avoid any statement like "...so God CAN", or "God MUST", or "God CANNOT..." because you've departed from the meaning of the word "God", to the Catholic, when you append a "so...can", or a "must" or a "cannot" to God. By definition, God CAN do anything, there is nothing that God cannot do, and God is not obligated or forced to do anything - there's no such thing as "God must."
It's not a small theological point. I have noticed over the years that many theologies have a limited God, who CANNOT do certain things. If a god CANNOT anything, then that god is not the same God as the Catholic God.
God can do anything. He is not obligated to do anything. He always chooses. He has free will just like we do, except that there is nothing impinges upon him to force his hand the way we are impinged upon. We make tradeoffs, and often we make them obliged by superior force. God is not limited by any superior force - his only limitations are his own views, his own opinions, what makes him happy.
He doesn't do things he doesn't like because he doesn't have to, and in general he likes his opinions (such as natural law) quite a bit. He can break natural law with a miracle any time he pleases, but it does not please him to do so all that often.
The "god who can't" isn't interesting, and to the Catholic, isn't God. The best that a Catholic could say, given our concepts of God, is that "God won't", but that's based on observations of the patterns of God's behavior, and does not constitute a natural law that is superior to God's sovereign will.
This is a sticking point between Catholics and traditional Jews and Muslims. The traditional Jewish and Muslim belief is that God CANNOT be anything other than a unique monad, God CANNOT have a son.
A philosophical Jew might modify that and say "God WOULD NOT have a Son", but the traditionalist, and the Muslim would assert that no, it is impossible, for unique one-ness is a fundamental essence of God that even God cannot transgress.
To the Catholic mind, that God WOULD indeed have a son is demonstrated by the fact that He DID, but to go further, the definitional stipulation that God CANNOT be anything but a unique monad means that such a God is not omnipotent, because he "cannot" something, and that is unacceptable to the Catholic mind. Omnipotence - Almightiness - is central to the definition of God - so it must always be said and believed that God CAN do anything. Whether he WILL or DOES or not is a factual question. That he COULD is essential to the status of being God.