Why do people choose extremes? They want the whole of something, or nothing of it at all. They want power, they want money, and so when they get what they desire, they will not share it among the less fortunate.
Why can't people see that moderation is the best option? They don't get too much, they don't get nothing, they get the right amount. But the Sins have corrupted humankind already.
Why were they released to corrupt the planet? I'll tell you why. Moderation is forgotten completely when curiosity is involved.