Erasmus struggled with the abuse of power that the leaders of the Catholic Church seemed to exhibit. An aspect of this criticism was based on the elaborate ceremonies the church led, which had little to do with the direct teachings of the Bible. This further extends to saints and patrons. Erasmus wrote that
Now there are not a few who are given over to the veneration of saints, with elaborate ceremonies. Some, for example, have a great devotion to St. Christopher. Provided his statue is in sight, they pray to him almost every day. Why do they do this? It is because they wish to be preserved from a sudden and unprovided-for death that day.
Erasmus felt that the Catholic Church encouraged believers to pray to and ask the saints for protection and safety and ignored the teachings and practices that led the saints to sainthood in the first place. He expresses the idea that church leaders should refocus their attention on giving admiration and respect to Christ and use the saints as their guide to how to do so. In short, the saints' words, not so much themselves, should be praised.
I have attached a fairly extensive educational article to this answer if you need access to more direct quotes from Erasmus or need further understanding.