We're an integral part of the current ecosystem on this planet. We are not killing the planet, we are killing the current ecosystem on the planet; i.e. we are killing ourselves.
We're not "killing" the current ecosystem. We're changing it, and causing a major extinction event. That's pretty impressive, for one species. But yes, it will almost certainly be to our detriment. I agree that we're probably killing technological civilization. That's still a long way from human extinction, however.
