People are dumb.
In this case though, I don't think their concern is so much motivated by stupidity but the fear that comes from the vague flash of realization that in the kind of socialist utopias they idolize, they become very much like the giraffes. It's self preservation by proxy.
Are you saying we euthanize each other to prevent overpopulation and inbreeding?
I'm saying that socialism and eugenics (and euthanasia) tend to walk hand in hand. When you shift the focus of a society from individual rights to group outcomes and make the government responsible for maximizing those outcomes, the idea that the government might accomplish this best by eliminating those most costly and least productive isn't a giant leap to make. It's not like it hasn't happened before.
I mean when folks say stuff like this:
George Bernard Shaw wrote:
You must all know half a dozen people at least who are no use in this world, who are more trouble than they are worth. Just put them there and say Sir, or Madam, now will you be kind enough to justify your existence? If you can't justify your existence, if you're not pulling your weight in the social boat, if you're not producing as much as you consume or perhaps a little more, then, clearly, we cannot use the organizations of our society for the purpose of keeping you alive, because your life does not benefit us and it can't be of very much use to yourself.
Many have argued that Shaw was just joking, or presenting a reductio ad absurdum argument. But then we'd have to assume he was also joking when he suggested making death chambers for the unfit and the need to develop a gas which could accomplish this quickly and efficiently back in 1910 or so. And maybe he was just joking around. But some people didn't think this idea was a joke, did they?
And hey. We'd have to also discount his support for Stalin's actions in the USSR in 1933:
But the most elaborate code of this sort would still have left unspecified a hundred ways in which wreckers of Communism could have sidetracked it without ever having to face the essential questions: are you pulling your weight in the social boat? are you giving more trouble than you are worth? have you earned the privilege of living in a civilized community? That is why the Russians were forced to set up an Inquisition or Star Chamber, called at first the Cheka and now the Gay Pay Oo (Ogpu), to go into these questions and "liquidate" persons who could not answer them satisfactorily.
So maybe not joking around. And while he was perhaps the most outspoken and publicly recorded socialist of his day, he was then just parroting the common thoughts of the day within those august intellectuals, who were all sure they knew better than everyone else how a society should be run. Great ideas, right?
Modern socialists insist that these things aren't part of their brand of socialism. They go to great lengths to distance themselves from these kinds of ideas, and especially anyone who actually carried them out. The horrors of the holocaust were so completely reviled that no one could continue to publicly associate any political movement with those ideas anymore. But they're still linked. What makes socialist theory "work" is the necessity of the state to somehow force people to be productive. You must replace the free market incentive of personal economic growth with something else.
I don't think it's hard for folks who live in socialist countries to recognize that they are more or less subject to the whim of the government for their livelihood. And that's remarkably like an animal in the zoo, isn't it?