Not long ago a question about how CRTs are installed in TV sets slipped thru without being marked as OT. It took just tree days for the next question about TV signal interpretation. Where the first in theory still have an effect on images displayed, the new one is in all parts unrelated. In fact, the OP seams to be quite aware about the dubious claim for OT and argues accordingly by citing precedence.
So the question is:
Should RC.SE move toward being a generic site for Retro eleCtronics?
It may be useful to really take a look at the question asked. Since it's safe to assume that any rightful designed video output will be according to its specs, the topic is strictly about configuration of a receiving TV set, not the computer or any part thereof. As a result it's about the TVs electronics and setup. In my book not in any way computing related.
On a more general note, This is not about a question being a good, interesting or intriguing one. OT-questions can still be on the cool side - much the one about intrinsic workings of CRTs asked with the 'Parallelogram' one is. Important knowledge about the fine details of CRTs, just not computing related.