The "supreme theory" is not mine. Please read the article on Ecclesiastical Abuse of Power which I have posted. This is the considered opinion of all the best theologians in the Church from time immemorial. The reason the pope's authority is not supreme is that he must, above all, obey the Divine Law which comes from God and on which Church law is based. That is to say, he must act justly in his dealings with others.
The reason the pope's authority is not supreme=the reason the pope'a authority is not supreme in the sense you suppose...