people are quick to call this edgelord shit when they were enjoying the story thus far, goes to show how conceited the readers are. It was established from the start what kind of person Jimi sensei was, and he acted in concordance with his character. His duty as a teacher comes foremost, even his personal feelings for the job ie even if he hates it, he will continue to fulfill his duties as a teacher but ofcourse this only extends to working hours so when the time is up he is free to speak his mind and cut through the facade, it's profound in a way because no matter how good of a teacher someone is they don't have to like every aspect of the job or any for that matter but when one becomes a teacher it is their duty to guide the students and that's what Jimi has done so far.