Would temptation not acted on cause bad karma?

I have a real problem with the idea of karma, its been hijacked in a way by new age philosophy to mean what you do comes back on you, but the original idea was simple, you are being punished in this life for your actions in your last incarnation. It implies that everybody suffering has earnt that suffering, i can't help but find the idea that children starving to death somehow deserve it, horrifying.