I finally caught up with this and I'm very glad I did. I didn't think it will turn out that good when I started…
Non is not completely innocent, he lets boys walk all over him. Was the Professor manipulative? Yes, But he had an expression like he liked it., even the little smile when Non left the room and blatantly lied to his boyfriend. Jin not the worst of the group, his only mistake was being silent and recording the video, I'm sure it was Top and Tee which disclosed, from what Fluke said in episode 4.