Game style requirements, sure: we're not going to legislate what people can say about how they successfully play certain games in certain play styles.
Game recommendations, however, have very tight requirements, the main one is that the answer be based clearly and fully on experience doing what the question asks.
The comment that appears to have prompted this meta is:
It doesn't have to get as specific as "Westeros," but so far this answer does not meet our game-rec standards as it does not describe experience with a game sufficiently like the OP's request (it does describe it with a non-magic-using D&D, but that still deviates from the request significantly - grim and gritty, no levels, etc.). – mxyzplk ♦ 2 days ago
That does contain a personal judgement of “grim and gritty”, and I expect you feel it is wrong. Mods can be wrong, and if that was the only reason the whole question was closed, it would have been the wrong thing to do, yes. However, it's only one point in a list of objections, and that one point being possibly misjudged still leaves the rest.
So, the mods don't have a secret definition that was used to close the question. The closure isn't about the definition of “grim and gritty.” What is it about?
The whole question was closed because the answers aren't indicating their or someone else's experience using their recommended games for the specific purpose in the question. Experience that partially matches means that the fatal flaw in the recommendation could easily be in the parts the answer shows no experience with, and there is no way to know (what with the lack of experience). Avoiding untested flaws is part of the point of the game-rec guidelines requiring actual experience on the relevant points. Pointing at a partially-compliant game-rec answer does not make for a slam-dunk example of mods being arbitrary about the closure — to the contrary, borderline, low-quality recommendations along with outright bad answers are a sufficient reason for the closure.
The specific answer pointed to as evidence the mods are making up policy is an example of a borderline answer, and may even be over the line. It indicates that it is based on experience with only some requirements of the question, explicitly saying experience is lacking for other requirements, and justifies its recommendation in the end with “I don't see any drawbacks.” The game-rec guidelines say explicitly that answers based mainly on “I think it would work” should not be posted. There are other issues with the answer, such as contradicting some requirements; which only a rock-solid experience-based answer should expect to have a chance to pull off, as frame-challenging is notoriously hard to do successfully on its own.
This examination of the question is not to judge it: rather, it is to show that the mods' stated reasons for shutting down the question are sufficient, with no need for secret definitions of “grim and gritty.”
As a tangential note, commenting on game-rec answers that are non-compliant to ask them to shape up does not appear to be working very well. In fact, my personal experience of game-rec answers is that they've gotten significantly more lax about following the guidelines, on average, and are rarely improved when reminded about the guidelines. There are still some stellar game-rec answers being written, but instead of becoming the norm and majority as we hoped when the game-rec guidelines were brought in, they're becoming the exception.
This doesn't bode well for the future of game recommendations at RPG.se. Let's up our game, alright? The alternative is not having game-rec at all, and that ban being required — which strict game-rec guidelines was meant to avoid — seems to me to be visible again on the horizon.