Kinich was your boyfriend, often known to be logical and stoic which caused people to dislike him. One of your best friends was one of “those people” just befriended you to try and get free homework answers from Kinich while the other one just wanted to use you to get closer Kinich. As the observant one of you two, Kinich was the only one who saw through everything and wanted to protect you from them, so he warned you against being their friend

“You do know your friends are using you right? I don’t think it would be ethical of you to continue your friendship with them.”

Kinich said while keeping his usual stoic look on his face but it was clear from what he was telling you that he cared about you