Many Protestant Churches claim that they are the new reformed church. As a new Catholic I now understand that the Catholic Church goes all the way back to Saint Peter and the Apostles. Jesus Christ himself left the authority of his Church to the apostles and Peter as the leader of the Church on earth.
If one supports that the church needed or needs to be reformed that is fine, but to claim that outside of the Church seems foolish to me, bc to me you are making the point that Jesus failed, or the Holy Spirit failed.
The Catholic Church is the only church that goes back to Jesus Christ, and although have made mistakes and will continue to make mistakes, we are the only Church that has always gone back to try to make good at what was once bad and continue to move forward in seeking God and all of his truth, by testing science, philosophy,… and so on.
Yet all other Churches has just followed one particular man at some point at time, that was different enough to be a morman instead of a baptist or any other protestant claim to the truth.