This place was truly much more than what Greek mythology allowed people to see. It did hold a large number of secrets that could not see the light of day. We realized that the creatures that had been held inside of Mt. Olympus could not be controlled with enough efficiency to make sure that they would not destroy the whole world. This is why we destroyed the entire mountain because we knew it would be easier to kill the creatures when they least expected it.
They would have wiped out humanity and we believe it to be too precious of an experiment. So far humans might not be what we expected but we are hopeful that they will evolve enough so that we can make all of this time worth the wait. Humans are like our little ant farm and we do not want to let it go to waste.