a) "I've flown Cessna 172s in MSFS. There is no way MD-83 landing gear will fail to come down"
b) "As a professional pilot, I can say unequivocally that no pilot would land in those conditions."
C) "I have flown the Concorde on transatlantic sectors, and once to the Antarctic Research Station and Alien Detention Facility in McMurdo Bay"
I don't recall anything like this being said and I didn't find anything via Search. Ironically you're criticising others yet justifying yourself with non-facts. If some such such non-sequitur appeared in one of these threads, you should quote that. This does two things - i) it potentially proves such a thing happened, whilst b) allows us to challenge your analogy.
Whilst it's true that professional airline pilots will know some things that armchair enthusiasts won't, the same is not true of logical analysis. I have two science degrees - Am I better than you at analysing theories? I don't know. You can't call it. However people like you want to. You want to say that only certain unspecified 'professionals' are allowed to theorize. It would be interesting to know what defines those professionals, incidentally. Being a pilot is not a qualification for analysing accidents although obviously it helps.
Try this analogy: pilots are like criminals, they have to use skill, experience and daring to do things in real time. Investigators are like policemen. They are slow and careful and have all the time in the World to think things through. Now tell me the only people who can be policemen are criminals or ex-criminals.