Their kamma is institutionalized morality based on what was considered right and wrong in pan-Indian civilization -- a law indeed, but an artificial one, meaning humans created it, not nature.
I remember reading an essay by Thich Nhat Hanh where he said that individual and collective kamma was responsible for the deaths in the 2004 tsunami.
When an aircraft explodes and crashes and nearly all the passengers die but one or two survive, we ask: "Why? Why did they not all die? Why did one or two live?" This shows us that karma has both an individual and collective aspect. When we discover the principle of individual and collective, we have begun to resolve a significant part of the matter already. If we continue in the direction of the insight of no-self, we shall gradually discover answers closer to the truth. It is very clear that when someone we love dies, the person who dies suffers less than those who outlive him. Therefore suffering is a collective and not an individual matter. Victor Hugo also found that human destiny is a collective destiny, and he caught a glimpse of the no-self nature of all that is. If any accident happens to one member of our family, the whole family suffers. When an accident happens to a part of our nation, it happens to the whole nation. When an accident happens to a part of the planet Earth it happens to the whole planet, and together we bear it. When we see that their suffering is our own suffering, and their death is our death, we have begun to see the no-self nature. When I light incense and pray for those who died in the tsunami disaster, I see clearly that I am not only praying for those who have died; I am also praying for myself because I, too, am a victim of that earthquake. All of us, to some extent, have contributed to the collective karma. A disaster that happens to any part of our planet earth or the human species is something for which we all have to bear responsibility to some extent. When others die, we die; when others suffer, we suffer. When others are in despair, we are in despair. That is the insight of no-self.