Sometimes, the person who understands oneself the most is always one's enemy, or rather, one's peer.
Earth Virtue Star Lord was able to rise in the Great Ming World and even procured an enfeoffment of a divine position as Star Lord, enough to prove his extraordinary means and strength.
However, he was after all an Independent Practitioner who had never truly joined a Sect, and did not understand how Sects operate, nor could he grasp the foundational principles of these powers.
Even though he had seen some powers rise and fall, heard some things from others, he had never truly experienced it himself, so at the end of the day, it was like looking at flowers in the fog, unable to truly perceive the truth.
But Water Virtue Star Lord was different; he hailed from a major Sect, and being able to obtain an enfeoffed Star Lord divine position also proved that he was even if not a revered teacher of the sect, still a core figure within. He naturally understood where the crux lay.