As a random thought, in the long history of this sub, had there been any answers that the author was writing off of personal experience as a participant, witness, or someone closely involved? E.g., "here is what people had and were doing in this place and time. Source: actually was there", or "yes, these events went so and so. Source: was member of the investigation commission after it happened", or something like that? I am aware of the "no anecdotes" rule, but I think that this case (eyewitness statement) skirts it from the "allowed" side.
The old Rules Roundtable and the updated Roundtable covering the Personal Anecdotes rule should provide a fair bit of insight as to our reasoning behind it. I'll just toss in a few more observations, as an interested amateur at this business.
First, my opinion is that the inherent anonymity of the internet renders most material here dead on arrival. You can cross-check a muffin recipe by baking it. There's no similar experimental process for history. Are we really sure that u/Gankom is or is not a bot? Were they really there for the Great Maple Syrup Heist of 2019? Can we confirm whether or not they're actually remembering something, or are they actually just making things up based on what they read about it? Are they or are they not actually the sockpuppet of some bored Ghanaian dude with a yen for non-fiction writing?
Verifiability is a pretty difficult thing on the internet, hence why we don't count people's credentials as a source. (Seriously, you would not believe how many people think 'I'm a PhD' or 'I have a BA' is enough to let a poor answer stay up.) And if, for instance, someone's personal experience of a thing were laid out in writing...well, cite the book, bra. (That'd be a primary source. Those things are weird.)
The closest thing we have to this is when the professionals comment on historiography they've played a part in - and even then, it's more about the quality and provenance of the scholarship. Take, for instance, u/Iphikrates commenting on Victor Davis Hanson's scholarship (more answers in this vein in their flair profile), or u/itsallfolklore's frequent mentions of his mentor, Sven S Liljeblad - this post, for instance.
But on the whole, anyone worth hearing likely has their story written down somewhere. Our theoretical member of the investigation commission likely can cite the report they produced, instead of just telling people "trust me bro".
An unusual example, but some years ago I answered a question asking about the 1992 demise of Punch, a 150-year-old British humour magazine, based on my contemporary experience of covering the closure while Magazines Editor of the "journalists' newspaper", UK Press Gazette.
I have answered a few questions here by using personal observations and my comments were allowed to stand.
One reply was about how people stored their food before refrigeration and I explained how my grandparents built and maintained their root cellar and icehouse. Another was about animal husbandry and I explained the method we used to castrate horses when I was young and how we do it today. The third answer was to explain how my family used horses to pack oversize and unusual loads.
I suspect they were allowed because I had been quite active in this sub regarding the history of Western Canada and my local region and my comments passed a credibility check by the mods.
I am unable to link them because they were made under a previous account which was banned for linking a facebook page containing names in another sub.