(Disclaimer: This isn't a definitive statement on what the guidelines on this type of question are, but a statement of what I would like them to be. Upvote/downvote agreement/disagreement accordingly, and if a mod comes along with a more definitive statement, feel free to ignore entirely.)
The only change this question needs is a more prominent reminder not to answer it badly.
Some questions are difficult to answer. They might require extensive research, they might need to pull from hard-to-find sources, they might need answers to be pretty long in order to cover all the important stuff, etc.
Some people on the stackexchange network are willing to go above and beyond to write good answers to difficult questions:
We shouldn't close questions just because they're difficult to answer, or we're discouraging this kind of beyond-the-call-of-duty excellence!
We also shouldn't hold ourselves to impossible-to-meet standards of evidence when answering history of gaming questions. This is a Q&A site, not a peer-reviewed sociology journal.
If I'm curious about whether a given behavior was accepted by mainstream gaming culture at a certain point in time, I'm happy to be presented with half a dozen magazine articles, blog posts, or campaign stories written by prominent community figures that treat that behavior as normative and/or unexceptional. I consider that to be pretty good evidence that, when those things were written, the behavior was broadly accepted (after all, the writings of prominent community figures often shapes community norms).
I don't need to see survey data from a guaranteed-to-be-representative sample of the population of gamers from the exact year in question. Like, obviously, if that data exists, I'd love to read about it. But if it doesn't, we don't have to jump straight from "this question can't be quantitatively answered to three significant digits" to "no good answer to this question is possible." If the best info available to answer the question is what Gary Gygax and friends wrote about it, then I would like to read that.
The question points out that the writings of a single community figure, even a prominent one, would just be an anecdote. This is true! But the writings of a few different community figures would be useful info; we shouldn't go straight from "one essay is just an anecdote" to "only scientifically collected survey data from a representative sample of the population of gamers is valid information."
Finally, the specific criticisms:
- Rather than drawing from a variety of verifiable (preferably published) sources like the question recommends, prior experience on the site leads to the belief that individual answers will nonetheless be of the unverifiable-one-lone-personal-anecdote variety.
"This question can only be answered badly" should be a valid close reason. "This answer has attracted lots of bad answers and no good answers" might be a valid close reason. "Someone might answer this question badly" should definitely not be a valid close reason. If people write bad answers, we should downvote them. If we don't give people the opportunity to write good answers to difficult questions, we're missing out on some of the best content that could otherwise be on this site.
Obtaining a general impression of gaming culture during that era is impossible because of a dearth of evidence. For example, gamers weren't required to take surveys and gaming groups' campaign details weren't consistently made public.
Even were a monumental amount of era-appropriate evidence somehow marshaled, no amount of evidence is sufficient to paint a general picture of an era. That is, any answer will be wrong at its core because generalizing omits specifically different groups.
These are covered above. We're not a peer-reviewed journal. Our standards of evidence don't need to be this high. I would love to read an essay that attempts to answer Hey I Can Chan's question drawing from a half dozen articles written by figures from gaming history. I wouldn't treat it the same way I would treat a scientific journal article, but that doesn't mean it shouldn't be on our site.