No, the church did not begin under the premise that the magisterium was supreme, but upon Scriptural substantiation, in word and in power. (Mt. 22:23-45; Lk. 24:27,44; Jn. 5:36,39; Acts 2:14-35; 4:33; 5:12; 15:6-21;17:2,11; 18:28; 28:23; Rm. 15:19; 2Cor. 12:12, etc .)
Infallibility belongs in a special way to the pope as head of the bishops (Matt. 16:17–19; John 21:15–17). As Vatican II remarked, it is a charism the pope “enjoys in virtue of his office, when, as the supreme shepherd and teacher of all the faithful, who confirms his brethren in their faith (Luke 22:32), he proclaims by a definitive act some doctrine of faith or morals. Therefore his definitions, of themselves, and not from the consent of the Church, are justly held irreformable, for they are pronounced with the assistance of the Holy Spirit, an assistance promised to him in blessed Peter.”
http://www.catholic.com/tracts/papal-infallibility
You can of course disagree with their theology, but according to the rules of the church, what the pope says goes, essentially. Non-catholics, of course, don’t have standing—even if they think they’re reading of the Bible is superior to the Church’s.