There's also no story of humanity where there is no ecosystem in the first place.
I think the hazard isn't in stomping on an exo-Earth ecosystem.
I think it's that if we can't avoid damage to multi-billion year evolved, robust ecosystems on our home planet, we might not successfully craft off-planet ecosystems that will sustain us indefinitely.
Not on the first go. So we should start early.
I think that learning how to craft off-planet ecosystems is a large part of what is going to help us stem damage down here. Where would solar power be now without the early adopters in the space industry?
And so...?
Even if true, that doesn't lead anywhere. If you're trying to faintly imply we shouldn't try, you ought to bring the arguments up to the surface, where examination will quite likely show they don't have that much substance.
We need maybe like 100 million or less people total on the planet. And 7 or 70 or heck 700 billion littered through the rest of the solar system. The chances of the survival of our species and life in general on the planet the would be infinitely greater than what we have done in the past 300 years. Population growth outside the planet raises absolutely no questions about the survival of the planet or species. The rest of the solar system is already completely and utterly dead as far as we know. No arguments about pollution or stability or sustainability or survival apply to it.
The rest of the universe as far as we know is our canvas, but please spare the damn planet from where we came. It's rare and nearly impossible to replace.
We are utterly destroying the only known home to life forms in the universe. We are doing it rapidly.
You seem to be living in a delusional parallel reality in which establishing a space society doesn't consume the resources of our ONLY current home planet and doesn't pollute it.
We must change our ideologies, our thought patterns, our cultures, and our entire industrial societies patterns and habits (not to mention energy source) within the next decades to survive, let alone thrive or develop further.
I don't get the sense that you comprehend our actual condition on this planet. There is a very very steep footprint curve with regards to both our population (There was roughly 1.5 billion of us the last time we all tried to kill each other, World War 2. Now there are 7 billion of us. Before, the consumption footprint of a person was rather low, now each person consumes more resources than ever before, and this amount of consumption continues to rise. The Chinese middle class will surely want every accessory their American counterparts have, right?)
How has this entire predicament avoided your scrutiny until now?
If anyone's living in a delusional parallel reality, it's you and your apocalyptic rantings.