Why are you surprised that imperfect people do imperfect things. By the way, all of us were created imperfect so that we would be able to learn and grow. The real issue becomes when some people fight against the concept of learning and growing.
Another way of expressing this is; some people are not conscious of the importance of waking up to their full potential and they then stay trapped within their ego driven mind.
The purpose of life is to consciously learn and grow so that you will contribute to the collective good, and not become destructive.