That's why I'd imagine they have rules about habitable planets in the galactic federation. You can't just go around landing on habitable planets and turning th

That's why I'd imagine they have rules about habitable planets in the galactic federation. You can't just go around landing on habitable planets and turning them into overpopulated toxic dumps after 300 years and repeating that exponentially. It's just not allowed. If it was, earth would have already been trashed by other E.T races thousands of years ago.