The inability to find attributes of a shared humanity in other people, such as the ability to love in the same way as others, goes to the heart of the problem (from my point of view).
Certainly, direct experience improves the imagination. I’m a hopeful Kantian on this point though. If one recognizes another human being as such, one should be able to imagine they possess the same human attributes as one’s self. Denial of humanity short-circuits this act of imagining.
I think Salecl (Perversions of Love and Hate) might have pointed out (paraphrasing) that envy of the pleasure of the Other is the source of hatred of the Other.