What is your evidence that they were exploiting the peasants?
Quite briefly: They not only demanded exemption from all kinds of taxation, but used the exemptions to profit from commerce in the commodities the peasants needed to live. In addition, they demanded the tithe. They held great quantities of the best (most productive) lands and used them for their own profit and not for the benefit of the people. They engaged in thought control both by denying learning and by threats of church sanctions for disobedience.
I think the evidence is hard to overlook.