"Too localised" is not the greatest wording for that flag, given JLU's focus. It'd be easy to make the point on many JLU questions that, being generally about some very specific aspect of one culture (often through an individual's own experience), they are "too localised" for a general audience... Yet they are perfectly fine JLU questions.
Either way, practically all recent "should this be allowed" questions on Meta have resulted in a flaccid consensus of "sure why not", due to the fact that any topic or form will have its supporters (and less-motivated detractors). I am personally OK with that (temporary, I think) status quo, especially as long as there is only limited activity on the site and it's easy to manage questions on a case-by-case. We may have to revisit some of the more lenient policies if/when the site ever gets really busy.
The one line I refuse to cross, is the test of "general interest to current and future users" (one could indeed call it not being "too localised"): no matter how strong its link to Japanese culture&language might be, if a question cannot possibly be of any use or interest to anybody beyond its author (and the occasional cultural doppelgänger), it should not be on JLU. This is also true, I think, of questions that might be fun to answer for current users (cf. recent trivia & games question), but potentially offer no interest to future users.
That being said: it is often only a matter of rewording, to make such questions acceptable.
When confronted with complaints that your question is "too localised", do some work on your end: extract the relevant parts (with a link to the fuller form for those who might want or need context) and formulate your question in a way that holds some interest even to people that might not share your exact infatuation for a band or other cultural artifact (if your question truly has a language component, that universality does exist).
Instead of asking people to guide you through the lyrics of a song
while sharing their feelings about it, pick the part you have trouble
translating/understanding, point out the exact
vocabulary/grammar/syntax you have a problem with and ask your
question on this part! (free to you to provide some short comments on
the context as long as it remains relevant to the question:
questioning people motives based on their inability to appreciate the
band's good looks probably isn't).