Tried systematically buying every alignment minus. Getting all of them yields "Nanobot light sphere consumes earth" which sets human population to zero. You must have accidentally bought an alignment bonus.
Tried a second time and yes I have successfully eaten humanity. Colonizing Mars didn't save anyone. Oddly enough I can still buy alignment upgrades (to WHAT?!) and GPUs (from WHOM!?). And the penalty for being eaten by nanobots is not -100% humans, it's -1B humans. So presumably if you overpopulate before you misalign you can survive the nanobots.