You don't need genocide to reduce population, just birth rate policies. Most developed nations already have declining native populations (sometimes the overall population grows only through immigration).
China had a one-child policy for a while. I think the world would be much better if other countries would restrict the reproduction of humans in a sensible way. Only those who can afford to bring up children with a minimum quality of life should be allowed to.
That's a solved problem. It worked in China without forced sterilizations. Just like how we have laws against theft… doesn't mean theft won't exist, but the law and appropriate punishment does reduce it to manageable levels.
China had a one-child policy for a while. I think the world would be much better if other countries would restrict the reproduction of humans in a sensible way. Only those who can afford to bring up children with a minimum quality of life should be allowed to.