The other weird direction it leads is space travel.
If you assume we eventually figure out long distance space travel and humanity spreads across the galaxy, there could in the future be quadrillions of people, growing at some kind of exponential rate. So accelerating the space race by even an hour is equivalent to bringing billions of new souls into existence.
You can make arguments for it starting with "killing billions of people would definitely be bad" or "some fraction of those people will likely share my genes, which I have a biological drive to pass on".
It encodes a slight bias towards human existence being a positive thing for us humans, but I don't think it's the shakiest part of that reasoning.
If you assume we eventually figure out long distance space travel and humanity spreads across the galaxy, there could in the future be quadrillions of people, growing at some kind of exponential rate. So accelerating the space race by even an hour is equivalent to bringing billions of new souls into existence.