Why so mean

I go through my students book randomly. I found out the most MEAN word inside it written by someone who shouldn't write such thing LAZY! in one piece of the book.I don't know what was the response from that student.In other pages the student asked to write again and again for nearly 100 times the same repeated sentences. What a shame that particular person only think about herself/himself without even consider what would happen to the student involved. I really regret to see and read the comment. I believe if that person rational enough she/he will not even think to write or ask student to do such miserable useless work. There's no learning part if the student punish with such evil way. To those who involved in teaching please consider your student before make any statement or punishment. Make them fully learn what you teach them and be able to carry the knowledge later. Don't make them evil in life because if they happen to do that you might risk the whole future generation. Think before do and don't ever think to involve yourself in teaching profession if you unable to control yourself.