Question

meaning of "jealousy is far above other filthy reasons why people kill"

Answer 1

It means that above all, jealousy would have to be the most heinous out of reasons to kill another person. This can be gathered due to the fact that, among millions of filthy reasons why a person would kill someone, jealousy outshines them all.

Answer 2

Or, it could mean that people kill out of jealousy more often than any of the other reasons.

Answer 3

I agree with both of your explanations, thanks.