Oh sorry! I mean the people who wrote the article. (Which is similar to the way Dan Ariely wrote in his book that people have no good reason to pick the $10 card, even though we do sometimes. He just concluded that we irrationally value free things more than we should.)
I think I'm concerned that by not providing any explanations, this article jumps into @Villiam_Bur's post's category #4. Other cultures are so different! They make these totally alien decisions with this game! If the researchers themselves did have explanations, then that makes the article even more sketchy because its authors decided to overplay the cultural difference instead of presenting the results as "probably if you were raised [like this], you'd also play this game differently" -- which is what the research likely found.
EDIT: I caught a weird bug where I keep saying "they" when referring to the article authors. I fixed it myself this time!
I mean the people who wrote the article.
The article isn't written by multiple people but by one person called Ethan Watters who reports about the scientific work of Joe Henrich and his collegues to a nonscientific audience.
As a result there are multiple different groups you could mean with "they".
I think I'm concerned that by not providing any explanations
Explanations aren't what science is about. Science is about having a theory and using it to make predictions. Then you see whether those predictions are accurately describing reality.
...
WEIRD may be weirder than you think. We Aren't The World writes of psychological experiments on non-Westerners that give vastly disparate results from results that have been assumed to be hardwired, and the implications of this:
Henrich used a “game”—along the lines of the famous prisoner’s dilemma—to see whether isolated cultures shared with the West the same basic instinct for fairness. In doing so, Henrich expected to confirm one of the foundational assumptions underlying such experiments, and indeed underpinning the entire fields of economics and psychology: that humans all share the same cognitive machinery—the same evolved rational and psychological hardwiring. The test that Henrich introduced to the Machiguenga was called the ultimatum game.
...
To begin with, the offers from the first player were much lower. In addition, when on the receiving end of the game, the Machiguenga rarely refused even the lowest possible amount. “It just seemed ridiculous to the Machiguenga that you would reject an offer of free money,” says Henrich. “They just didn’t understand why anyone would sacrifice money to punish someone who had the good luck of getting to play the other role in the game.”
...
At the heart of most of that research was the implicit assumption that the results revealed evolved psychological traits common to all humans, never mind that the test subjects were nearly always from the industrialized West.
Edit: The actual papers this article writes about are covered in this post by Ciphergoth from a few years ago.