But killing old people, past their reproductive years, has no long-term effect on population, except maybe through extremely weak high-order effects like "the a

But killing old people, past their reproductive years, has no long-term effect on population, except maybe through extremely weak high-order effects like "the availability of grandma to watch the kids may subtly affect reproductive decisions" or "old people come from an old culture which is more productivist, and may influence their descendents ideologically".