Interesting take. Inequality or unfairness definitely seems to be a pretty common factor for breeding hatred.

There's another factor that I think may be even more important: fear.

It seems any time one person (or group) hates another person (or group), it's because they ultimately see the target of their hatred as in some way threatening their fundamental well-being or way of life.

I think inequality often increases the perception of potential threat, but I think the fear can happen in the absence of inequality as well. And if the fear is there, the hatred can be there also.