It has NEVER been Catholic theology that God determines whom's saved and whom's not.
Catholics have always (argued, anyway) that it is The Church that saves and without The Church one couldn't be saved.
Thus; what you say now is a reformed thought process.
It is God who saves through the Church, which is the body of Christ.
Keep in mind that this is not restricted to card-carrying pew-sitting parishioners. The Catechism (Link) puts it well:
"Christ's Spirit uses these Churches and ecclesial communities as means of salvation, whose power derives from the fullness of grace and truth that Christ has entrusted to the Catholic Church. All these blessings come from Christ and lead to him, and are in themselves calls to "Catholic unity."
"Furthermore, many elements of sanctification and of truth are found outside the visible confines of the Catholic Church: the written Word of God; the life of grace; faith, hope, and charity, with the other interior gifts of the Holy Spirit, as well as visible elements.
You can easily see that that deals with the salvation of other Christians outside the membership rolls of a parish, yet not outside the Church (whether they know it or not.)
Saying "Who saves, God or the Church?" is analogous to saying, "Who saves, God or Christ?"
Christ IS God. The Church IS the Body of Christ.
What are your qualifications for telling people what Catholic theology is, and isn't?
This is Catholic theology, in fact, it's infallibly taught Catholic theology.
Protestants sometimes have the temerity to say that the Catholic Church doesn't actually believe this.
They're wrong. She actually does. Today. Right now.