When a user comes to Ling.SE with an etymology question about a word or words that can be traced back to a language with a major written tradition like Sanskrit, Greek or Latin (say), it seems that some users tend to close the question as off-topic as they are more philological than they are linguistic, while others tend not to (as they edit the question without voting to close).
Intuitively, I agree that such questions do not seem to be particularly linguistic, as they are more likely to be studied in departments like classics or area studies, rather than linguistics departments. However, I often have doubts as to whether I should vote to close these questions. This is because if someone were to ask for the etymology of a word from an 'exotic' language family or branch such as Pama-Nyungan, Algonquian, Gur or Polynesian, etc., my intuition would be to accept such a question (even though I've never seen such questions here myself). This is because linguists in linguistics departments do study etymology in these languages.
Another possible reason for rejecting etymology questions is that they aren't useful for other visitors to the site. But while syntax trees and language identification clearly fall into this category, etymology seems less clear-cut. It could well be that more than one person wants to know, say, the common origin of the different words for 'night' in Indo-European languages.
And finally, I found this in the FAQs, listed among the acceptable question types:
- a single word in relation to multiple languages or a single word/single language
Does this imply that etymology questions should ordinarily be acceptable?