The hate is stemming from resentment. That resentment is being weaponized into a political force, and all the emotions stemming from that resentment are being back-rationalized because of it. This is "you have the right to hate your oppressors" narrative.

The cruelty is a moral imperative because they assert you can't suffer like they have, and they have felt cruelty to them (which is really based on the resentment for others that they have, and being denied what they feel they deserve, but never actually earned).

If you don't live in resentment, all the other negative emotions that stem from that can't happen. These people are basically school shooters, as intended by an industrial scale psychological and emotional abuse system.