A "moot point" or saying a point is moot, as a phrase, is frequently misinterpretted. It is frequently used to mean a point is irrelevant, not up for debate, not worth debating, or the speaker simply doesn't want to argue anymore, all of which are incorrect.
The ancestral meaning, regarding moot court, may still be in use in some places, but I will focus on the other definition.
Definition: moot point (plural moot points)
An issue that is subject to, or open for discussion or debate; originally, one to be definitively determined by an assembly of the people.
An issue regarded as potentially debatable, but no longer practically applicable. Although the idea may still be worth debating and exploring academically, and such discussion may be useful for addressing similar issues in the future, the idea has been rendered irrelevant for the present issue.
Until we rebuild downtown, whether we build more parking spaces is a moot point.
Now, where people tend to go wrong is in the bastardization of the second definition. In your case, you removed the most vital portion of the definition, the central portion of the definition -- that the point is debatable. Every definition of the word focuses on that primary point, and many people forget that. It is the origin of the word, and it has never lost that meaning.
The point I would like to make is this -- to be a moot point in this second definition, the point must be both debatable and no longer applicable or relevant to the current case. This includes the definition in the US legal sense as well. It isn't that a subject isn't worth discussing, rather that it no longer has a practical application in the current circumstances.