Something that is specific to RPGs is on topic here. Something that could equally be on topic on SciFi and Fantasy or Biology or whatever is relevant for the subject at hand is not. See the programming.SE Venn diagram that's popular to clarify this. "Genre" is not for this site, it's for genre sites - this is "gaming."
Furthermore, these questions are on a short leash anyway because they are not totally congruent with our core vision per the FAQ - "practical, answerable questions based on actual problems that you face." "I wuz wonderin'" is not an actual problem. Pure history of gaming questions (marginally) get a pass on this, but history of random tropes also used in gaming don't. I know I considered closing both those questions but decided to let the community act on them first. Of course people are trying hard to change them into history of gaming formatted questions to avoid the close, but I'm not sure of the core value. "Where did X come from, where did Y come from" generate noise and rep but I'm not sure they're helping real gamers play or run their games.
Now, it's fair enough when someone's ignorant that the thing is a real world derived item (dire wolf, vampires can't cross running water), but that seems like then it's a "I didn't bother to even google it myself before asking the question," which is poor form - this SE is supposed to be experts helping experts, not people just whirling off questions to entertain the masses.