What are we trying to achieve as a species?
If we can't answer that question then we can't really judge our actions effectively. If we view humanity as the most intelligent life form not just on the planet, but in the entire universe, then we are the only source of order in an infinite chaos. All of reality is just entropy and mindless cruelty except for humanity.
Viewed in that lens we almost have a duty to expand before some cosmic event obliterates us. Granted we are expanding in a moronic way and our goal seems to be to make plastic trash for people to mindlessly run through, but still, It would be nice if politicians occasionally stepped back from the narrow view and thought about what was at stake.