Literary analysis of works of sci-fi and fantasy should be on-topic ...
One of the close-voters made the argument in comments that "This doesn't appear to be about sci-fi, it appears to be about writing." But we already have a huge number of questions about works of sci-fi and fantasy which aren't specifically about the sci-fi or fantasy elements and are considered on-topic. Questions about works of SFF are on-topic even if they're not about the SFF elements. See also How should we handle questions that are about non-SF/F elements in a SF/F work?
... as long as they're answerable with more than pure speculation.
Of course, being "not about sci-fi or fantasy" isn't the only reason to close a question. And in fact, this question was closed by 4 votes as "too broad" and 1 as "primarily opinion-based" (although reviewers were fairly divided on whether or not to close it at all, and 5 people have already reopened it by now).
So, are literary analysis questions closeworthy even without being off-topic? Well, in general certainly not: we have a literary-analysis tag with 19 questions only 2 of which are currently closed, and also a meta discussion at Is critical analysis now off-topic? (spoiler: no, it's on-topic). Literary analysis of works of sci-fi and fantasy is a valid thing to ask about on a site about sci-fi and fantasy.
Such questions can be harder to answer well than fan-trivia questions, since they're usually not answerable by a single passage from the book or quote from the author, but require more actual subject knowledge and expertise to answer properly. I'd encourage people to downvote answers to such questions which are based on unsupported opinion, but to upvote answers which are supported by convincing arguments. Note that such answers don't necessarily have to be objectively, canonically, correct - it's possible to make a compelling argument based on other things than canon quotes. See also Good Subjective, Bad Subjective and the help centre guide on subjective questions:
Some subjective questions are allowed, but “subjective” does not mean “anything goes”. All subjective questions are expected to be constructive. What does that mean? Constructive subjective questions:
- inspire answers that explain “why” and “how”
- tend to have long, not short, answers
- have a constructive, fair, and impartial tone
- invite sharing experiences over opinions
- insist that opinion be backed up with facts and references
- are more than just mindless social fun
If your question is about [the] writing of science fiction or fantasy, ask on Writers Stack Exchange.