[Humans are] the worst disgusting and gross, leave their trash everywhere. They think all history was made in order for their own creation. They pollute everywhere they figure out how to get to.
Do not mistake the ineffectiveness of other animals to be "care" for their environment. A beaver will happily defoliate acres of land. Cats can depopulate entire species of birds, given the chance. Rabbits will breed far beyond the capacity of their environment to support their numbers. All of them will "pollute" as readily as man, leaving their waste wherever it may drop and not taking particular care to "clean up" after themselves when they are done using a burrow or nest. Certainly, they show no evidence of caring about other species; other animals are prey to be fed upon, or predator to be fled from, or other to be ignored but never a concern beyond that.
Humans aren't perfect, to be sure, but our problems are largely due to own success. Though we would believe ourselves somehow superior to the "lesser animals" with which we share the world, we are still moved by the same base impulses of our distant cousins. However, our cleverness with tools and our extreme adaptability means that we are more resistant to environmental repercussions with which the system uses to self-correct the actions of its more boisterous inhabitants. A wolf-pack that eats all the deer in its territory is likely to starve next winter, but Men will just move to a new territory or import food from its neighbors, and thus the genes of the "over-eaters" are preserved rather than culled. Alas, now that our territory encompasses the entire world it may require a worldwide disaster to rehabilitate Man.
But then again, maybe not. Because we are learning - however slowly it may seem - that not only are our resources not unlimited, but also that the Earth is a vast and interlocked system which we share with all the other species on the planet. This very concept of environmentalism is fairly new - a few hundred years at most and truly popular only for the last two or three generations - and prior to this Men took little concern to their depredations because they always thought there would be an endless supply so long as they moved to the next horizon. Now, we are reconsidering our actions - acting against the very instructions of our genetic make-up - working to preserve what we have. While it is not entirely without self-interest, nor is it entirely selfish; we preserve other species for no other reason than a belief that they have as much a right to exist on this planet as we do. That is more than any other species on Earth has done.
Our impact on this planet has been devastating, matched perhaps only by the impact of micro-organisms or the insect kingdom. But these mistakes are only because we follow our genetic predisposition to breed to capacity and do not believe for a moment that any other species on this planet would do any different. Certainly we should use our intellects to curb our innate predilections but neither should we entirely condemn ourselves.