You can argue that they are not providing constructive feedback, but the claim was:
>a person tries to add happiness to their life by taking it away from other people around them
>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.