This is a great question and not easily answered.
The example question illustrates how site norms change over time. A site will start off quite relaxed and open, members welcome all sorts of questions even when they might be only tangentially related as these questions help get a site underway.
As sites get more established they tend to become more conservative and members are a bit stricter in their judgement of whether a question is a good fit. Stack Overflow went through the very same thing a few years ago - there was an undercurrent of deletions of some very old and quite famous questions because they no longer fit the site's current direction. This was raised at the meta level and some quite lively discussion took place - for every question someone proposed to delete there were an equal number who wanted to keep it because it was part of the fabric of the site. To fix this issue Stack Overflow introduced the historical lock.
So the fact that you are asking this question is a great indicator - it shows the site has matured and progressed.
Back to the example question - should it be closed? To me it is asking a question that is related to the practice of martial arts. It doesn't matter that a specific art or technique isn't mentioned - the martial arts context is implicit and in this case the tags add context.
As a community member you can cast a close vote at any time, nothing is stopping you. The only thing in question is whether the rest of the community supports your judgement.