Should such questions be allowed? The information is easily available to the person who needs it and they have no benefit to the community at large.
That and I'm starting to get annoyed by them :)
Sometimes, manuals are hard to understand, and particularly can be confusing to new photographers. Often, the information is there but it's just hard to find if you don't know what you're looking for.
In these cases, I think these questions are fine. And generally, we've erred on the side of answering them rather than making a fuss about just how basic is too basic.
Several times a manual says HOW the happy path scenario works but not WHY it works like this or what happens in alternate scenarios.
A lot of times the manual does not cover all possible combinations of settings found in a camera.
Here are some of my questions where the manual did not help me at all (even though I read it before asking)
Should such questions be allowed?
Yes, absolutely. We get lots of questions about specific models of cameras, lenses, speedlights, etc., and it's a good bet that a lot of them are answered somewhere in the manuals for the respective products.
The information is easily available to the person who needs it and they have no benefit to the community at large.
I was out taking photos today when I had a problem with my camera. I didn't have the manual with me, but I had my iPhone. 30 seconds of searching turned up the answer I needed (not in Photo.SE, regrettably). I have no doubt that the answer is somewhere in the manual, and I suppose I could have searched for the manual instead, and then tried to download and read a multi-megabyte PDF on my phone. But someone before me had already asked the same question, and gotten a great answer, so finding exactly the piece of information was a piece of cake.
TL/DR: the manual is often not easily accessible when it's most needed, and the community definitely benefits from having answers.
One point I would like to add: Often when you buy a used camera online there is no manual that comes with it. Most of the time there should be a manual available to download somewhere but not always. Usually it gets more difficult with older cameras.
Making this a rule wouldn´t be fair.