In my opinion, these types of questions are subjective, and could possibly even be closed as decorating advice.
Here's the latest example of this type of question:
Should these types of questions be off topic?
I think so, yeah (and just flagged the one you linked). All of the advice or recommendations mentioned in that question (align with long edge of room, long edge down hall, long edge along light from windows) are aesthetics - i.e., decorating advice. There is no structural reason to align the planks one way or the other. And when you have conflicting advice (as in this case), there is no clear cut way to resolve that conflict, since all three choices are valid! That is kind of the definition of subjective / decorating advice.
There may be some aspect which is on-topic (as @RedGrittyBrick mentioned, maybe fewest cuts / least amount of waste), but I think that'd be a stretch.
Not always subjective imho. A bit of information about the current condition of the subfloor can easily make the answer objective.
For example, a 1/2" subfloor that is newly installed and glued is obviously able to support any direction of flooring. But still begs the question if you're spending 10k on something that is supposed to last a life time, don't you want it done as solid and stable as possible?
I say no: it's entirely on topic.
The answer may be that "there is no correct way" or that "it's subjective as to which way is correct based on design" -- but IMHO that's an entirely valid answer.
Some things in construction are done for aesthetic reasons, others are done for safety or structural or practical reasons, and to a newbie [in that area] it's not always obvious which is which.
Let's pretend the answer to this question is "You never want more than 5 or 6 planks that are less than 3' long in a row, or they'll start buckling as humidity changes" (to be clear: this is not true). I may be wrong, but if this was true, then I think this question (maybe reworded slightly) would be considered on-topic, and this to me is the problem: whether the question is on-topic or not should not depend on what the answer is.