Or "Cosmic", I'm guessing these words have a common ancestor.

Here's a concise, practical explanation (theory) for why this is (theory) practically a universal human impulse (feeling).

Your mind is spinning trying to think of how to "get even". But plain old punching back has no evolutionary advantage. You punch back and you get stuff: wife, daughters, flint, dried organ meat, an atlatl...

Getting even involved getting free stuff too back before "property rights" and "jail", and that does have an evolutionary advantage.

Being unable to fathom there being no cosmic justice is the end result of being deeply wronged and never getting any kind of actual earth justice. We stew and stew upon how ol' Gog ran off with your longest stick and the elders don't plan on doing jack shit about it.

That's why. It's nothing special. It's two earth animals interacting. Sometimes you get the hit end of the club.