It really depends on the tradeoffs though. Preserving a handful of hyper-specific species (eradicating which would still be the worst case scenario and hardly a given) is arguably much less useful than heavy lift launch capacity.
The truth is that we are killing off the planet way faster with other means than we are with rocket development, so these decisions don't exist in a vacuum. The faster we can heavy lift tons of material in to space, the faster we will get outer-space industry up and running. The faster we do that, hopefully the less destructive we can be on earth. For example, wouldn't it be cool if we were able to mine lithium-rich asteroids instead of destroying entire regions with open-pit mines here on earth?
As I see it, expanding into space is one of the few ways we can continue to grow and progress as a species without further decimating the earth by necessity. Certain people in our society would prefer that "progress" just halts entirely and that we should care more about preserving [insert random animal or plant species here] than about the future of humanity, but I can't really agree. And more importantly, there are other players on the board that don't care at all about the externalities, so it seems important that the players who actually care try to lead the way, lest they get left behind and the environmental destruction happens anyway.