How did the protest at Speyer contribute to the name Protestant?

The name "Protestant" originated at the second imperial Diet of Speyer in 1529.12

During this assembly, the Roman Catholic emperor Charles V sought to rescind a 1526 decree that had previously allowed individual rulers to decide how to handle the Edict of Worms, which had declared Martin Luther a heretic. In response to the emperor's demand that religious dissenters end their separation, a group of princes and free cities—led by Philip, landgrave of Hesse—formally protested the decision.2314

These leaders argued that the majority decision did not bind them and declared that, when forced to choose between obedience to the emperor and obedience to God, they must choose the latter. Because of this formal "protest" against the repeal, the participants and their followers became known as "Protestants". Over time, this label was applied to all who adhered to the tenets of the Reformation.2134