You wrote:
“Perhaps then the Pope should rescind Luther’s excommunication.”
If Luther had just been an honest man there would have been no excommunication. Remember, Luther wrote to Pope Leo X on May 30, 1518, Luther, “Wherefore, most blessed Father, I offer myself prostrate at the feet of your Holiness and give myself up to you with all that I am or have: quicken, slay, call, recall, approve, reprove, as shall please Thee. It rests with your Holiness to promote or prevent my undertaking, to declare it right or wrong. Whatever happens, I recognize the voice of your Holiness as that of Christ abiding and speaking in Thee. If I deserve death, I do not refuse to die.” [The English language translation here is in, The facts about Luther, by Patrick F. O’Hare, p. 89. The text in the original language, which I am assuming is Latin, is in Knaake, in “Werke, Weim, ed., I, p. 522.
Two years later, NOTICE: TWO YEARS LATER, on June 15, 1520, in Exsurge Domine the Pope warned Luther that he risked excommunication unless he recanted nearly four dozen of his ideas within 60 days.
Luther burned Exsurge Domine in public on December 10, 1520.
Luther then was excommunicated by Leo X on January 3, 1521, as laid out in Decet Romanum Pontificem.
In other words, Luther was a liar, while Pope Leo only very slowly got around to excommunication him - after giving warnings and plenty of time to shape up.
My personal favorite of Leo's demands was #33, that Luther repudiate his statement: "That heretics be burned is against the Spirit". Luther could have chosen to have continued in his fealty to Leo and publicly agreed that the Pope was doing God's work when he ordered heretics to be burned or he could have taken a stand for righteousness. He chose the latter.
Of course, Leo's threat to Luther was that, unless he recanted, the princes of the church could "...proceed against him to his condemnation and damnation as one whose faith is notorious and suspect and, in fact, is a true heretic with the full severity of each and all of the above penalties and censures". Luther's reaction to this bizarre papal bull was to treat it with the same dignity and respect with which Leo ordered Jonathan Eck to treat the writings of Luther; that is, to burn it.