If any of you wish to destroy humanity, the only choice is to include yourself to the mix, because no matter how much you try to deny, you're part of humanity, and you're just as good and bad as the rest. And you may be the worst for killing off the rest.
How have we messed this planet up? Only humans know how much we messed it up, the environment, mother nature and the universe couldn't care any less what we do. Animals only care of their own survival, and if given a choice, they won't kill off everyone of their own species if they're given the chance to. Self-termination of our own kind makes us worser than animals.