So, question asker here. I'll try to explain why I think this kind of questions should be acceptable.
I understand that "finding the correct translation" of a term is often opinion-based, especially if this is a relatively niche term that hasn't find its way in the dictionaries (and of course if the term had found its way in the dictionaries the question would be off-topic for a completely different reason). However these kind of questions seem to be well-received in other language SE sites. For example, both English.SE and French.SE have whole tags about them (1, 2, 3 and 4).
Aside from that argument from authority, language is a slippery topic, and we cannot expect the same amount of exactness in the answers to questions based on language than, for example, questions about mathematics or programming. "How do I say this?" is a concrete problem that people have when speaking a language that's not their own (or, as in my case, that is their own but that they do not use in certain contexts). It is true that there is often no "right" answer (and sometimes no answer at all!), but such is the nature of the subject.
If we allow people to ask only questions we are sure admit a unique answer, this site would devolve on little more than a transcription of Serianni's book together with some of the more interesting articles by the Accademia della Crusca. We can do better than that, without losing sight of the limitations and goals of the SE format.
That said, I agree that such questions should not devolve into discussions. I would strongly suggest to stick to the format of "one answer per post" and be more aggressive than usual to move comments to chat.