Politics, religions, cultures, views of reality all greatly differ, yet morals are largely consistent. Why is it just so naturally consistent in the arena of morals, but not these other areas?
Because humans are intelligent, tribal, social animals. The differences in behavior among all of the above are simply the size of the tribe and the power of the leaders. But even the strongest leaders are bound by the simple tribal morality of respect for tribe members, follow the leader, and ultimately do what mama tells you to do before you are six.