The problem with leaderless uprisings taking over is that you don't always know what you get at the other end. If you are not careful you could replace a bad government with one much worse!
Even more than this, however, the sick - like lepers - were often reviled because people believed that they had brought their torments upon themselves.
If God creates a world of particles and waves, dancing in obedience to mathematical and physical laws, who are we to say that he cannot make use of those laws to cover the surface of a small planet with living creatures?