Yes, we need to quit fighting fellow Catholics and concentrate on serving God and fighting the devil. That said, sometimes we need to oppose a fellow Catholic if we are sure he is fighting for the devil. This is normally the job of the bishops, but if they fail, it falls to the priests. If the priests also fail, it falls to the laity, the men first, and then to the women and the children. Remember, God once used a stupid donkey to speak for Him!