I thought it was an excellent example precisely because it's so disturbing. It's about as close to objectively true as you can get: "human life is a precious thing" is a value judgment, and you can't logically prove value judgments. It's also a value judgment that virtually everyone would agree with, which illustrates that many things that everybody believes cannot be objectively proven.
Incidentally, you could make a logical argument that the reason everyone believes "human life is a precious thing" is because anyone who doesn't has long since killed themselves or been killed by people who wanted to preserve their precious life, and you can do so without passing any judgment on whether human life is in fact precious. One could easily imagine AI robots, for example, who don't believe that human life is precious because it doesn't matter to them whether we kill each other all off. But this separation between the object level ("here's what I value") and the meta level ("here's why I value it") is fundamental to making logical inferences.
> It's also a value judgment that virtually everyone would agree with
The interpretation of this judgment has varied a lot across the times. Historically, in less individualistic societies, I think that the loss of human lives for the good of the group was considered less taboo than today. There were also different interpretations of what "human" meant, obviously, with the life of slaves, strangers, women, different-looking people, etc., being less precious.
People from the future could find that they disagree a lot with our current interpretation of "human life is precious". Western societies today don't seem to care much about the fact that human life in most of the world nowadays isn't "precious" in the Western sense, so this might be a shock to someone from the future. More generally, we are fine today with the fact that everyone dies eventually, whereas a futuristic society having achieved practical immortality would perhaps see each individual death as a catastrophe.
A clarification: the argument I'm saying we could make is a factual-level argument of "the reason humans believe that 'human life is precious' is because those humans who don't have long since killed themselves. Its structure is similar to Descarte's 'cogito ergo sum', something like:
"In order for someone to have a belief, they must exist. In order for them to continue to exist, they must not have taken any action in the past that would lead to their death. People who believe that human life is not precious are significantly more likely to take actions that will lead to their death. Therefore, people who believe that human life is not precious remove themselves from existence at a higher rate than those who believe human life is precious, and so the vast majority of people will believe human life is precious."
You can quibble with the premises and I won't defend them, but you would agree that this argument takes the form of a syllogism and hence is a logical (if possibly false) argument. My overall point is not about whether human life is or isn't precious, it's about the distinction between object-level and meta-level. On the meta level you can make a logical argument, from falsifiable premises, about why people might believe the statement "Human life is precious". But on the object level, that statement is a value judgment, and so that statement can't be approached with logic in any coherent way. You can argue about the truth or falsity of whether & why people hold certain values, but you can't argue with the values themselves. (Logically, at least; you can always argue using various fallacies like argumentum ad auctoritatem or argumentum ad baculum. Indeed, applying the results of your analysis of why people hold beliefs to whether the beliefs are right is an example of the ad hominem fallacy.)
'Human life is precious' is not a truth in any sense of the word. It is a feel-good slogan, coined by humans for humans. You cannot possibly define it rigorously enough to start worrying about its trueness. The example is poor and is clearly reaching for shock value.
Neither my comment nor the article ever says 'Human life is precious' is true. What the article says is "'Human life is precious' is something you believe not because of logic, but because other people told you to", which I do believe to be true. It's up a meta-level from the level that you're discussing.
The article claims we all believe human life is precious for illogical reasons. Gasp! Comment section erupts in arm chair philosophy. All because they allowed the author to conflate formal system rigour with philosophical nonsense. That is, 'mathematically logical' and 'thinking rationally.' You cannot apply rigour to vague bumper-sticker slogans, they are trivially illogical. Almost nothing is completely logical in daily life. It's not a big shock. There is nothing profound about this. To assume otherwise is naive.
You say "It's about as close to objectively true as you can get." If by 'objectively' you mean 'extremely subjective to the human experience' then I agree with you. Otherwise, I'm not sure what you're on about.
Recognizing this point about irrationality puts pressure on any philosophy to be able to deal with a mixture of reliable and unreliable actors acting in various interests. This means that absolutes are very risky. Including the bumper sticker.
> "It's about as close to objectively true as you can get"
I read that as you saying that "Human life is precious" is true, though maybe I have misunderstood. (Don't take this as that I agree with the other guy though).
Oh, I was referring to the full clause in the parent post ('one of the examples they provide for "things you believe not because of logic [thus, it's objectively true], but because other people told you to" is "Human life is a precious thing"') and to the example in the article. I thought that was clear from context ("an excellent example", plus "human life is precious" being mentioned rather than used in my explanation in after the colon), but it's a long phrase, and it's admittedly pretty confusing because the example is itself talking about whether certain statements are objectively true.
Incidentally, you could make a logical argument that the reason everyone believes "human life is a precious thing" is because anyone who doesn't has long since killed themselves or been killed by people who wanted to preserve their precious life, and you can do so without passing any judgment on whether human life is in fact precious. One could easily imagine AI robots, for example, who don't believe that human life is precious because it doesn't matter to them whether we kill each other all off. But this separation between the object level ("here's what I value") and the meta level ("here's why I value it") is fundamental to making logical inferences.