But when I was a student, everyone really had this mentality.

I work hard to take notes and don't want others to get something for nothing.

For another example, many people will prevent their deskmates from copying their answers during the exam. Especially between two students with similar grades, this situation is becoming more and more obvious.

Maybe it has something to do with my faint heart of comparison.

So you don't have to feel guilty or uncomfortable because of this mentality. Everyone does.