The most obvious problem with the quoted excerpt is that the Scripture never mentions one getting his or her sins forgiven through a complex church hierarchy. It is given by a Person, and His name is Jesus Christ (John 14:6; Acts 4:10-12). Our sins are washed away by His shed blood (Hebrews 9:13-14; 1 John 1:7-9; 1 Peter 1:19; Revelation 1:5). We are justified by accepting the gospel, which nowhere demands a complex hierarchy. The mercy of God is not limited to an institution or a set of rituals. Nowhere does Scripture say that His grace is imparted or communicated through some human institution.
There is another problem with the quoted excerpt from the Roman Catholic catechism above not readily apparent to a cursory reader. Scripture tells us that only God knows the hearts of man (1 Samuel 16:7; 1 Kings 8:37-39; 2 Chronicles 6:30). Rome does not have that ability. To claim that the Roman Catholic Church has the authority to forgive our sins is to assert a human institution in the place of God, and so is presumption in the highest degree.