Why is "karma" so feared?

I'm of the view that such things do not exist. Karma is a perspective of innate universal balance, and is instead rather unrealistic. The only possibilities to karma being possible would require reincarnation and then must insist punishment or empowerment based in karmic effects from past lives. At that point, the supposed justice of the universe would never seem to be actual justice upon those who have committed certain positive or negative acts. In my view, the concept of reincarnation karma seems even more unlikely due to the basic determinism that overpowers the supposed free will in human life. Determinism makes karma infinitely more complicated and quite unnecessary.