The order came to earth for a very simple reason and that was to make sure that we had plenty of experimental species to work with all over the universe. We are stationed in hundreds of planets and we are always performing all kinds of new experiments on all of them. To be perfectly honest one of the most intriguing, but also least useful planets, has been Earth. We are intrigued because the human species are so flawed but somehow they have been able to evolve into a better race.
The problem with this planet is that the humans have ruined a lot of resources and continue to destroy it because they are still not evolved enough to know how not to ruin it through inventions and science. We came here to see just how much we could help them evolve without being too involved in their decision making process.