But then again, it's Paul speaking.....
I've noticed that Roman Catholics do not understand what the Law is with regards to Jesus Christ and salvation.
Thus they cannot see the necessity of the sacrifice fulfilling the Law, once for all the sins of His flock, nor do they understand that Christ alone did just that on behalf of His sheep.
This may be due, in part, to Rome's ignorance of the Old Testament and its insistence that the OT has very little meaning to the New Testament, when in fact all Scripture is God-breathed. The OT and NT make up ONE BOOK wherein God reveals to men who He is, who they are, what they are supposed to do in the present, and what awaits them in the future.