Since you acknowledge there are some cases, I'll do some real talk too. I think people who always obsess over something they claim to hate, and allow it to color their perception of every interaction they have, have some type of unresolved issue. A secret desire for the thing they obsess over is a common one, but you're right, there are other causes. Else, unless they're hurting others, why such a high emotional investment like hate on people who are just living their lives?