Wiping out the species you're trying to save is obviously ludicrous. The point of this article is that rats (which are dead common in practically all corners of the world) pose an enormous threat to lots of unique species and ecosystems, and controlling rats is necessary if you want to preserve those unique species and ecosystems.

Spreaking large amounts of poison to do that, certainly makes me quite uncomfortable. But I'm no conservationist, so I can't really judge whether that's ultimately a good or bad idea.