I can't believe that I'm being (for lack of a better term) attacked for being pro-human. First, you changed your argument from worst to most destructive. I can see an argument for most destructive, so I'm going to respond to "the worst" claim.
Of course the human population has done things that are bad. I think that you are arguing total effect is worse than everything else because we have the intellect and ability to do more harm than other species.
But where you are missing the point is intent. Humans as a species show more compassion towards others than (almost) any other species. Some of the more intelligent species can show compassion to others and even other species, but that is usually limited to family units. I could list/link countess stories about human compassion and you in turn could list/link countless articles on how people have destroyed things and been terrible and then we'd be right back where we started. But the fact is its not as bad as the news makes it seems. Remember, if it bleeds, it leads. (Most) People are good. If you disagree with that then I have to think that you believe that a) Most people are bad, but you're one of the good ones, which is narcissistic b) you are bad and everyone else is like you, which I hope not or c) the bad people are the ones in charge (which may be the case).
That's what I think.