You can draw the line to personhood anywhere you wish. All you need is a pseudo-rational argument and lots of political supporters. If there are two things you can always count on they are human ego and selfishness. People love their own personality and pleasure above all else.
History will continue to repeat itself. There will be more and more genocides and future generations will learn nothing from them or draw completely the wrong lessons. Liberals think that the main lesson to be learned from the Nazis is that government shouldn’t use too much surveillance. They aren’t even bothered by genocides anymore.
The best thing that can ever happen to anyone is to not be conceived in the first place. This world is hopelessly vile.