I do not know how to treat such questions as this one https://tex.stackexchange.com/questions/150006/changing-to-a-vertical-table-in-latex. It is not a beginner's question. Moreover, many patient suggestions at the earlier posts of this user seem to have no effect.
Is there a recommended policy of behaving in such situations?
a) Downvoting, b) recommending to close as unclear, c) ignoring or d) anyway answering e)your suggestion if any?
Here's my take on the options you give.
A. Downvoting: No, as has been commented in the comments to the question, more downvoting doesn't really help. A downvote to -1 (with comments) should be enough to spur the OP to edit their question. If it doesn't the extra downvotes won't spur them on more.
B. Close as unclear: No. Or certainly not immediately. It's always better to err on the side of waiting before closing. Let the person address the comments, and don't close too early.
C. Ignoring: Yes. Or at least waiting to see whether the question gets revised appropriately based on the comments.
D. Answer anyway: No. If the question is so unclear, I don't think there's much to be gained from an answer that is a guess. Put your guess in the comments if you want to stake a 'claim' to that kind of answer.
The bottom line is that we don't get masses of these questions, so when they do occur there's no great need to deal with them with great speed. Also, we can never assume that real life hasn't interfered with the OPs ability to respond immediately to comments. This is another reason why swift closing is not in anyone's best interest.
Think of it this way: how is it detrimental to you if someone asks a bad question? The simple answer is "Not at all." In the longer term, it might be bad for the site if there are lots of bad questions, but we have plenty of remedies for that, including the monthly Answer the Unanswered sessions, where such question can be closed at that time if there has been no response to comments.
One other comment: Although a user's past behaviour might elicit comments about it, I don't think that past questions should have any effect on how we deal with any particular question. Each question should be treated independently, and the fact that someone has failed to respond to comments on a previous question shouldn't cause us to act differently towards the current one.
