I think that the creativity or destructivity of humans is largely affected by some of our inherent human qualities, some good, and some bad. We have this desire to find, discover, understand and explore, and that is probably what channels our creativity. However, we also tend to be selfish (of ourselves or of our race) and ambitious, which both drives us to create while also causing destruction.
Interstingly, you've got terror attacks and genocide which may appear to solely destroy, being driven by negative motives such as anger and revenge, but I've notice that looking further reveals that there's a motive to create... something. I believe the Holocaust was part of Hitler's plan to restore Germany after a political, economical and social collapse caused by World War I, and even terrorist attacks are intended to create fear.
So perhaps we are creative beings, or at least we are driven by our desire to create (or simply make an impact), but it can bring alongside destruction, if we do not care.
Personally, from my own world view (of intelligent design), I believe that humans were designed to create, but became a destructive race due to a number of events in history. It's definitely an interesting discussion. ^.^