Actually, it's used towards those that could not defend their positions (i.e., someone who hates something just for the sake of hating it or simply because other people like it).It's ghetto-speak from the early 1990s, employed primarily by those who could not defend their positions.
No, by -- people who assert or promote something and are unable to defend it, so they simply label those who question them "haters".
That certainly seems to be the way it's used here.