I don't think there is a need for specific policy about legal questions separate from other off-topic questions. I can't view the linked question now since it was deleted, but I think questions on such matters are often simply off-topic as they are not really financial in nature.
As a counterpoint to Ben Miller's answer, though: I think we should be cautious about rejecting questions just because they are about a real dispute. If an answer gives incorrect advice or wrongly leads the person away from contacting a lawyer, etc., when that is what they really need to do, then that is a problem with the answer. We should not close questions just because they might lead to bad answers.
Many questions that seem to be of the form "How can I resolve dispute X with person Y" may allow for answers that provide information on the underlying personal-finance issues without attempting to actually resolve that particular dispute. (For instance, we have seen many questions about credit-card disputes with merchants or issuers that can be answered with information on how credit cards work, how user liability is limited by law, how problems may be avoided by switching to a different bank, etc.) I think answers can give useful and relevant information on many such matters, even if the original asker feels unsatisfied because his/her individual issue wasn't "solved".
In short, we should not reject questions that ask for advice on a specific dispute. We should just not give answers that fall into the traps Ben Miller mentions when they try to resolve that specific dispute. Instead, we should give useful information on the topic of the dispute, insofar as we can. (Of course, there are certainly questions that don't provide enough detail to even take a stab, and I think it's fine to close those as unclear if the asker doesn't edit to add needed info.)