I have long told people that at its core, karma is the belief that the rape victim really did have it coming.
OK. I’m sold! No more Karma for me!
Xlnt point. I will use it when appropriate.
There are varying degrees of Karma. Karmic debt as you describe above can be used by some to explain bad things happening to otherwise good people or explaining how someone could be born with a serious genetic abnormality. In many cases it is easier for people to find some reason behind things. Many people do not like the fact that random chance occurs in life.
Is it any different than trying to explain original sin?
The Karma that most people think of is of the "you reap what you sow" variety. Which is also an eastern religious explanation of Karma. If you lead a sinful life and continue to make non-virtuous decisions you will start to pay the price in this life for those decisions.
Karma is a nice short word. As a Christian I can use it to mean the within this lifetime kind of karma. In using it I don't necessarily have to buy in to a reincarnation philosophy.
With that said while it's not standard Christian philosophy there have been Christians that believe in reincarnation. The early gnostic Christians, General Patton, my Aunt for instance.
If I have faith that Christ paid the debt for my sins, does a distorted metaphysical world view negate that? If my faith would save me from Hell would it not also save me from future lifetimes if they existed?