From a history of the Anasazi/Hopi and their cannibalistic ways, a practical argument for eugenics:
2. In any community there will be fallout—undesirable people, and people who drain resources.
Even if the members of a survival bunker are chosen carefully, the issue will always come up. The violent and antisocial; the sick, weak, mentally ill and disabled; contrarians, critics, activists and crotchety old farts. Decisions will be made about who the fallout are, and what to do about them.
3. You can’t just throw the fallout out of the bunker.
If you throw out troublemakers, they could easily become an outside threat. You could throw out the sick and weak—but people in the bunker wouldn’t like it, and there would be public outrage. After all, every single one of us is eventually going to be fallout.
4. The fallout consume precious limited resources.
They need to be watched, fed, housed, cared for, treated, maybe even confined in a prison or medical or psychiatric facility. That requires a huge chunk of limited bunker resources—and quite often, it doesn’t even solve the problem. While these attempts to remediate fallout are good for morale, they need to be kept to a minimum to conserve resources.
The author uses the example of a bunker, but this applies to any isolated population, including one that is struggling with resources or enemies. When you have a goal, people who stand in the way of that goal become enemies.
In the case of the Hopi, apparently their method for handling people they did not want was to slaughter and eat them like cattle, which is commendable for its honesty. Consume that which is not needed and move on.
The “fallout” consists of all those who are not useful at achieving the goal. Egalitarian societies hold the useful, useless, and destructive in equal estimation, but that may merely be the bloat of a society that has lost direction.
As democracy continues its slow downward spin into third word grey race oblivion, we are going to see groups willing to use the primal form of eugenics, exile, to remove useless eaters and bad genetics alike.