There's a long history here. I want to start a thread on it at some point.
As we know, supernatural faith involves both the intellect and the will. More and more the intellectual part was understated in favor of the good will, all in line with philosophical subjectivism from the Renaissance to Descartes to Kant.
Molinists started by emphasizing free will over grace.
Right around that time, the mostly-Jesuit theologians started to question the necessity of explicit belief in the Trinity and Incarnation for salvation, claiming that natural truths can in fact be believed with supernatural faith.
So, over time, supernatural faith in objective truths about God took a back seat to the will to believe what God teaches, and ultimately replaced it entirely.
Thus we have Vatican II and the ecclesiology of the sincere, subsistence ecclesiology, ecuмenism, partial communion, and ultimately religious liberty. It ALL FOLLOWS from this subjectivism. Many of the Traditional Catholic bishops and priests acknowledge subjectivism in Vatican II but they refuse to recognize its roots in the erosion of EENS over time.