Well yeah, because of our ingrained sense of morality & self-preservation. But we're talking about the policies of society so it's kind of pointless discussing them if you don't accept that society should exist in the first place.

Also... it's not society, it's the human species.

That's indeed a philosophical question. Should we even exist at all?

It's a strange thing of nature and evolution that it creates a species that can plan and execute its own intentional suicide.

It's fairly irrelevant to the discussion. All societies that choose not to exist also choose for all their policies about (not) reinforcing children to not exist.