>In subtractive, a person tries to add happiness to their life by taking it away from other people around them - putting people down, criticizing, picking on people, name calling, etc.
>a person tries to add happiness to their life by taking it away from other people around them
Read it however you want, but taken in context I disagree that that's their intended claim. I think that poster meant that malicious criticism is something that can make unhappy people feel a little better about themselves.
Also, "criticize" as a verb tends to be more negative and imply a more direct attack than "criticism of" or, even better, "critique" which both shade towards implying giving the person more useful feedback.