That policy was perceived as necessity. There is little evidence that population growth leads to economic growth - overpopulated countries typically have low living standards.
Our government here in Canada is a perfect example of a government who claims to take good care of environment - - all while extensively using private jets and doing other things that do way more damage.
The point is that it is best to give as little power to one's government as possible - hence why we need to cool our heads before we give our government any additional powers on environmental issues.