That's assuming that all the harm we do, we do it just to do harm. I think this assumption is false. Most of the harm we do is a side effect of things we're trying to achieve.
So, basically, we're just another (slightly smarter) animal.
It's not like, for example, invasive species introduced from another continent stopped for a second and thought: "hey! maybe we shouldn't breed too much and we shouldn't eat all the bees/birds/whatever!".
Life is like a gas, it expands to fill all the space given to it.
I don't think that's inherently bad. After all, life is the exception in the universe. And frankly, most of the universe is boring :)
Do you honestly find that to be a better explanation of human history the past few thousand years than "humans are evil, and the cause of all nature's ills"?
Personally, I find the latter proves true to life. Better to accept it and deal with it, than to sweep it under the rug.