Euthanazis today (and their troll friends here), without saying so, apply exactly the same utilitarian standard to determine who shall live: fitness to work ["contribute to society"]. Those who are net consumers of resources have, in Richard Lamm's memorable phrase, "a duty to die."
Again, Dr. Klein at least knew the evil he was doing. The likes of Peter Singer, Arthur Caplan and Richard Lamm are clueless.
[Colonel Backhouse] Q: Will you tell us what happened on selections?
[Dr. Klein] A: Dr. Wirtz, when the first transport arrived, gave orders to divide it into two parts, those who were fit to work and those who were not fit, that is those who, because of their age, could not work, who were weak, whose health was not very good, and also children up to the age of fifteen. One looked at the person and, if she looked ill, asked a few questions, but if the person was healthy then it was decided immediately.
Q: What happened to those people who were selected as capable of work?
A: The doctor had only to make the decision. What happened to them afterwards was nothing to do with him. [I vuss chust vollowing orderz!]
Q: What happened to those people whom the doctors selected as unfit for work?
A: ...I have heard, and I know, that part of them were sent to the gas chambers and the crematorium.
They had them figured out to the penny, and as you say, the trolls do that to. To them, it must mean to kill the weak saves them money. How nice.