As I sifted through this information, it suddenly hit me that lending money on the condition that it be paid back with interest is morally wrong. It is inconsistent with reciprocal altruism, the principle underlying cooperative behavior between non-relatives. The idea of reciprocal altruism is that I do you a favor with the expectation that you would do the same for me, and, in the future you (or someone else in the group) will do something for me of equal value. It is tit-for-tat, not, "I'll give you some food if you give me 20% more than what I shared with you."
Today, have-nots in society are forced to borrow from those who have, for a price. Someone who is born into a wealthy family can sit back, living off the interest gained from lending, while producing nothing of value. We've come a long way (in the wrong direction IMHO) from the days of reciprocal altruism.
Actually, the situation is even more despicable than I just described. The financiers of today are no longer lending money backed by actual property of value. They loan money that they do not have. They gamble, hoping to gain on the losses of others. It's a dirty, evil business.