Subtlety
Subtlety in fiction often includes not explicitly saying what a character does or why they do it—leaving it up to the reader to be able to figure that out.
So I think part of why some science fiction readers (including, to some extent, me) are sometimes a little dubious about that kind of subtlety is that some of us are geeky enough that we don't necessarily understand (or entirely trust our own understanding of) some human behavior.
We humans spend a lot of time interpreting other people's behavior. We watch what they do and listen to what they say, and watch their faces and bodies as they say things (if we can see them), and we make guesses as to their motivations.
And most of the time most of us are pretty good at it. But I suspect that to some readers, certain stories read like puzzles—not science puzzles, but human-behavior puzzles. And if you're good at solving science and math puzzles, but not so good at interpreting human behavior, then you may end up feeling frustrated and dumb. And if you're like me, you hate feeling dumb.
All of which is a roundabout way of saying that we're back to the Audience Question. What can you assume about your readers? Will their cultural expectations color their reading of the story? (Hint: The answer is yes.)
On the other hand, the readers who do have the cultural background that you're expecting will be bored and annoyed if you spell it all out for them. Hell, I get annoyed at the obligatory explanation of the Many-Worlds Interpretation that's required by law to appear in every alternate history story not written by Howard Waldrop—but my first exposure to that idea came from science fiction stories, and authors and editors have to assume that at least some readers won't be familiar with the idea.
As usual, I have no answers.