“Nice try, but the Protestants were not mere protesting against the pope but of all the bishops and 1500 years of Church teaching.”
The Reformation started with Luther protesting against abuses being sanctioned or perpetrated by the pope at the time. Principally, indulgences.
The abuse concerning the sale of indulgences was by Johann Tetzel, not the pope. In any case, if Luther had just opposed abuse, he would probably be hailed as a saint today, just as many saints who did so. No, his main objections were with long established Church teachings, and not just abuse by the pope.