Let me give a less "formal" answer than Wrzlprmft's one.
In my experience, style guides are seldom complete, and are frequently of not-so-easy interpretation, especially for novices. I saw people advocating the closure of questions about style by saying "read the style guide!", when the style guide doesn't even exist, or is either incomplete or seldom ...
The ease of research is easily underestimated and we can produce valuable answers to such questions.
Therefore, we should not have a close reason or general policy to close such questions.
Instead, we can use existing mechanisms to deal with these questions: comment, downvote, and (in extreme cases) close as unclear.
Canned Close Reasons
We can ...