A similar thing seems to have happened on “At the clinic” vs. “in the clinic” “At the clinic” vs. “in the clinic” which was closed as a duplicate of How do American English and British English use the definite article differently?How do American English and British English use the definite article differently?
One of the answersOne of the answers on the "original" question concluded with The general rule is 'in X' for being part of the institution, but 'at the X' or 'in the X' for being physically related to the building.
Although superficially the two questions look quite different, I felt they both covered much the same ground. And since the answer to the second was already present on the first, closevoting seemed reasonable to me.
In that case, it was the fact that the same existing answer could satisfy both questions that led to my decision. That doesn't apply in the particular case raised here, but it does seem to me the second question simply raises a "sub-issue" within the original, that didn't happen to be explicitly addressed by the accepted answer (but where a simple comment would probably have been quite sufficient).
I know I'm not going to win this argument (OP's question has already been re-opened), but I do think it would be better to refine and extend the scope of existing questions/answers so they address a broader range of yet-to-be-asked future questions, rather than constantly creating "near-dups".
TL;DR: Quality over quantity - one good Question & Answer is better than several mediocre ones.