Seeking tranquility and freedom from fear, and limiting desires, seems entirely compatible with monastic life.
Ahh, but all error has some truth in it. Nothing wrong in wanting tranquility and simplicity (for God gives such blessings to us too) but the error lies in making such the goal of life. The monastic life can lead to peace and tranquility but the Epicureans were violating the natural law (as did most of the Greeks) to attain their “heaven on earth”.