Boys are called monsters by girls, okay? Is it positive or negative?

Literally, it is not praise, but affirmation. In fact, it is still biased and cannot be said to be derogatory.

However, the most important thing is not what to call, but who to call, or what kind of mentality this person is.

Just like some parents call their children "dog eggs" and "rabbits", it is not derogatory.