Source of hate comes from these mainly;

someone's insecurity
someone's low self-confidence
someone's competitiveness
someone's perfectionism
someone's jealousy / feel of possession
someone's envy / feeling without
someone's love / overwhelming passion they don't know how to express to person or topic
someone's lack of self-esteem

someone's belief if they suffer or have conditions to living then all should suffer / have conditions to living

someone's belief all people should be treated equally despite being different / very unique

(last one above might a type of discrimination with 'go-to-do intentions that rise above actual logic that the uniqueness we all have is undoubtedly not equal or the same or needs the same / wants for the same etc... and can even be oppressive!)

I'd like comment on that last one especially as I'm quite sure... but would like to hear potential flaws
(if we are going to have a next wave of governing (ideally not government but being together as sovereign entities (sound paradoxical perhaps but just catering for each individuals own pre-sets as well as trying new, if all can be honest enough)

And feel free to add to the list or even if you encountered it today... write!