Let's reanimate a forgotten proposal: how about renaming x-literature language tags to x-language? For example, tagging things as french-language or russian-language instead of french-literature or russian-literature.
- Since they are effectively language tags, it's a more precise term for what the tag is for.
- The new names would make sense as tag names: it wouldn't be weird to see a question about the Shahnameh tagged as persian-language or about Borges stories tagged as spanish-language, for example. (The x-language-literature names suggested on the previous meta post are very long and unwieldy, and it's not really necessary to include "literature" in the tag name.)
- It would eliminate the confusion that exists for some tags where the language adjective coincides with a country's adjective. (Why is there french-literature but no swiss-literature? Maybe not obvious to a new user.)
- It would also eliminate the problem you raise in this meta post. Perhaps a Ukrainian author writing in Russian wouldn't like to see their works tagged as russian-literature, for political reasons unrelated to the language (and more related to the previous bullet point, conflating countries with languages). But surely they wouldn't mind seeing them tagged as russian-language: this is an objective fact about the books, and helps sites such as ours with organisation.
I think "let's respect the wishes of the author" is a fine sentiment, but it has the potential to get complicated in the future. How do we find out the wishes of the author? What if the author has said different contradictory things in the past? What about long-dead authors from times when languages were different? Tagging according to language is more objective than country/culture/identity, which are a bit harder to define. (I know languages aren't always clear-cut to define either - hello, scandinavian-literature and kurdish-literature - but at least clearer than ethnic identity.)
For our site, tagging according to language makes sense. It's not a political statement, just a bookkeeping decision. But to make clear that that's what we are doing - e.g. that the Russian tag is only about the language of the piece of literature, rather than the Russian Federation or its predecessor states - we can put "language" right there in the tag name for unambiguity.