Since it was said by Catholic monks and is about the initiation of the Protestant Reformation, it's probably fair to say that this was not meant as a compliment. In fact however (according to Study.com) Erasmus was loyal to the Catholic church, although he did think it needed reform.
Wikipedia quotes an article in the Concordia Theological Quarterly from 1977: "Erasmus wittily dismissed the charge, claiming that Luther had hatched a different bird entirely."
This probably wasn't meant as a compliment either. Erasmus and Luther disagreed fundamentally over the issue of free will: Luther believed in predestination (that all events have been willed by God), but Erasmus "lampooned" this view in The Freedom of the Will (1524). Luther, for his part, once described Erasmus as a "viper," "liar," and "the very mouth and organ of Satan".
© Haydn Thompson 2021