I don't like flowery lead-ins, so to cut to the chase: in my humble opinion karma is a metaphore, not an actual thing. Frequency is, and the Galactic sages refer to the Law of Attraction: frequency attracts like frequency. If you harm life then you acquire that frequency and will attract entities that do the same. That's why it often seems as if there exists a hidden equalizing force that passes moral judgement. In my opinion frequency is just a mechanism. Whether you acquire a frequency as a perpetrator or as a victim makes no difference in what you attract with that frequency. Personally, I have spent decades trying to figure out what karmic lesson there was to be learned from a certain kind of trouble that kept returning. I now think there isn't any. The more past lives I become aware of, the more I realize that sometimes a frequency isn't due to one thing, but the superposition of many things, possibly leading to a system of equations with so many variables that it becomes impossible and irrelevant to determine how you got that frequency. A frequency may originate from past-life trauma and attract entities or people who carry that frequency for whatever reason. For me, the issue emerged when I ascended to 5D, some 30-35 years ago and low frequencies started to surface because they collide with the 5D frequency bandwidth. Only now, that past-life traumas are surfacing for resolution can I hope to get rid of this particular pesky frequency that I referred to.
If frequency is amoral (not based on morality), does that mean the Universe is amoral and couldn't care less how people behave? Not at all, because there is but one Lord of Karma: your Higher Self. On the 3D Earth it is possible to virtually completely ignore the Higher Self (your soul), but sooner or later your HS will overtake you if you don't listen, often by illness or other discomfort, or by drawing to you experiences it feels you need to have, to learn and grow. The trick is to distinguish between the voice and needs of the Higher Self and things that result from frequency. I needed past-life rememberance to do that.