I think that Bender was right. Until the Swissian Anabaptists, nearly every Christian reform group had seen itself as the only true Christian Church and the inevitable successor to Catholicism. Anabaptists were the first who boldly claimed to be "a" Christian Church next to other Christian Churches. This was completely new and unheard of (at least in the Western world).
Erasmus may have been a promoter of tolerance within a closed organization, but he did not promote tolerance between a plurality of organizations. He did nothing to promote freedom of association (and disassociation), which is the at the center of well-understood "liberalism" or libertarianism. (He has nothing to say for people who try to disassociate themselves from the LGBT crowd. )