They left behind a crappy mess. It was wrong, it was immature,it was irresponsible, and it is exactly what you and I do to the rest of the earth. Everywhere we go there are crappy messages. Whether it's lead in the water, oceanic islands of plastic, oil spills, strip mines or the  coffee cup you just threw out the window of your car. The humans dump their crap everywhere. File under #leastfavoritespecies.