Deep man.

Maybe we are supposed to be cleaning it up for our "higher race" that it is out on another planet. Or maybe they are cleaning one for us somewhere.

Maybe we fucked up our Creators planet and when they come back they are going to kill us all and start over on anothe planet. Or maybe we made it perfect for them.

Maybe they can't survive on oxygen. Maybe they need gases that are poisonus to us. So we die anyways. And they return.