This is not about any particular person’s faith; when I say “objectively” I mean theologically true (as God sees it). For example, a Lutheran may believe that Lutheran and Catholic Churches are equally pleasing to God, and it’s just a matter of what helps an individual grow in faith more or what an individual likes. While this would be his subjective opinion, the reality (absolute truth) is that the Catholic Church is more pleasing to God because it’s His Church, not just as an institution, but He is the bridegroom of the Church. For this reason, the Catholic Church is the only one fully faithful to God - it contains the full truth of God’s revelation. Other Christian denominations contain partial truth and therefore are not fully faithful.
The definition of faith I’m using here is from New Advent encyclopedia:
Objectively, it stands for the sum of truths revealed by God in Scripture and tradition and which the Church presents to us in a brief form in her creeds.
The sum of truths revealed by God is found in its entirety in the Catholic Church.
This doesn’t mean that individuals in other churches are not pleasing to God, or that Catholics live out their Christianity better - it’s not about that. It’s an assertion that there is a qualitative difference between the Catholic Church and all other churches at a theological level.