Answers that are simply wrong aren't supposed to be deleted. Answers that are supposed to be deleted are not answers at all.
What you've outlined in your question isn't a non-answer. Worst case scenario, it's a bad answer.
So, you're really asking:
What should we do with bad answers?
And the answer is simple, even if we don't do enough of it on Code Review: downvote it.
So, from a language-agnostic approach, here's a set of points to consider when you're thinking about posting an answer in a language other than what the question asked it in (or when you're in a position to up/down vote such an answer):
- Does using the other language mean rewriting the entire project in the new language or can the languages be mixed in the same project?
- If the answer to the previous question is "they can be mixed", does mixing the languages mean a lot of overhead (importing some big library or framework that may not otherwise be imported)?
- How comfortable is the OP with the alternative language? What impact will this answer have on maintainability from the OP's perspective?
- Is the alternative language's approach actually really that much better than the original language posted in?
- Does the alternative language actually work well for the constraints the OP is working in (ex. recommending C# for an OS X project)?