Have you ever heard about any other species that have caused an another whole species to be extinct?
You should not because no animal is as evil as we are.
I think its not about being demonic. Perhaps people destroy their environment or kill a lot of animals oblivious of their number simply because they are not well informed on the repurcussions. Perhaps, they needed to survive. Perhaps, they do not have any idea on the impact of what they're doing.
In the end, yes. We are nature's most destructive beings but, we are slowly correcting that by our countless efforts and innovations like advocating animal rights and welfare, environmental clean ups, promoting ecofriendly products, etc.
We, as human beings are innately compassionate and kind. The perception that we are demonic- as I define demonic as an act aimed to kill, torture and destroy at one's own pleasure- is baseless and wrong.