There are many worlds that have been stripped of their natural resources and have become barren as a result.
Certainly, terrestrial worlds such as yours are rare, maybe one out of five or six thousand planets contain the biological diversity that you enjoy and take for granted here in your world. That still accounts for many planets in the universe.
But such planets are always occupied, are always valued and the native races always have to defend their rights, their privileges and their stewardship as they begin to emerge into the Greater Community.
Terrestrial planets create biological hazards for visitors. And that is why colonization is usually attempted once the native race has either established a usable network that the visitors can use, such as is the case here on Earth, or have destroyed themselves through conflict and war, leaving an open door for intervention to occur, even military intervention.
Military intervention is allowed in this region of space under such conditions. This represents part of the ethics of contact that are assumed and are practiced by many nations in this part of the Greater Community.
Passage from The Allies of Humanity, Book Three, Seventh Briefing.