Have you met a bully?

Usually bully has a reason that they bully, but their targets are just whoever looks like an easy target. If it turns out that they are, they keep them.

Who gets to have kids?

The poor? The blacks? The Jews?

Forcibly reducing birthrights is absolutely genocide. Unless you are talking solely of reducing birth rates within your own ethnic group…I wouldn’t call Chinas “one-child” policy genocide, per se, but it absolutely paved the way for systemic infanticide. And that’s not really significantly better.