The reason? A small phrasing change in the game's Chinese version.
Originally, a space shuttle on the game's main menu had the phrase "不到mun非好汉" written on the side of it. In English, the phrase roughly translates to "One who fails to reach Mun is not a hero," which referenced a famous Chinese saying, "不到长城非好汉," or "One who fails to reach the Great Wall is not a hero."
However, the game's developer caught some flack for the particular wording of that phrase, with one Steam user going so far as to claim that the literal translation of "好汉," "good man," was sexist in that context.
The developers have since changed it to "不到mun不罢休," which means "I will not stop until I reach Mun." That's where the controversy begins.
According to Splinter producer Isabelle Niu, who I consulted for aid on this story, the Chinese saying, "不到长城非好汉," or "One who fails to reach the Great Wall is not a hero," is attributed to Mao Zedong, founding father of modern China, and despite the phrasing, is not colloquially understood to be gendered.
"Although 好汉's direct translation is a 'good man,' nobody actually thinks of it that way," said Niu. "Its most accurate translation should be 'hero' or a 'man of honour.' ...Little boys and little girls visit the Great Wall and then claim to be a 好汉."
Steam users have not taken kindly to the change. "New Chinese translation '不到mun不罢休' has lost the beautiful feeling of Chinese traditional proverb," reads one of nearly 300 recent negative reviews, summing up a common sentiment.
Others simply print the original version of the phrase alongside a thumbs-down. Also, a not-insignificant number of others rant about "Feminazis" and "political correctness," because of course they do.
I reached out to the game's developers to ask if they plan to change the phrase back to its original form, but as of publishing, they had yet to respond.
For now, Niu told me she's actually "vaguely" in support of the change "just like I think 'firefighter' is better than 'firemen'" and because "language has unintended consequences." But it's also easy to understand why Chinese Kerbal players would favour a translation that more closely adheres to a famous cultural saying.