Not Catholics, the Institution.
The Church has sought knowledge that isn’t in the Bible to support their positions.
Unless you are going to argue that Pope Francis is supporting positions that are Biblical, then you have to understand that he and his Cardinals and Bishops are making use of knowledge that isn’t Biblical and they got this knowledge from somewhere.
>> ...he [Pope Francis] and his Cardinals and Bishops are making use of knowledge that isn’t Biblical and they got this knowledge from somewhere. <<
Sin and knowledge about it are not secret—there is sin and attraction to sin in every man’s heart. While gnostic (secret knowledge) societies like the Masons may advocate sin, it doesn’t mean that sin is some sort of secret knowledge. They just position stuff like that to make it more attractive to gullible people.
If it is De Fide Catholic teaching, they got it from Tradition passed on from the the Apostles, as learned from Christ Himself, and from the Holy Spirit, who He promised us He would send to teach us all Truth.
If you’re referring to the blatantly non-Catholic nonsense that Francis is notoriously promoting, then yes, God only knows where it is coming from. I suspect you and I both could make a pretty good guess.