@ Philisopher
“every human being makes mistakes. Imperfection is one of the traits that defines a human being. Only Hashem is perfect, only Hashem does not ever make mistakes.”
If one believed that (a) due to a persons inherent perfection he will not make a mistake then you are right. However, If based on a misguided understanding of emunas chachamim, one believed that (b) Hashem is committed to guiding leaders such that they won’t make a mistake this would not be a”z.