I had a pompous, academic-sounding dull contribution, complete with references to the 1854 amateur investigation into the Soho cholera outbreak, but thought better of it.
90% of all contributions are questionable, and they don't discriminate by profession. Every job involving professionals has non-professionals who go about telling the pros how they should do their job. That Widget-factory owner has his fan club too -- just check the minutes of the annual meeting, or his stock forum. If you want to know how bad it can really get, listen to a Sports radio talk show.
Any intellectual endeavor that involves sifting through data should welcome additional (and non-standard) sources of data as well as interpretations, as long as it bears in mind that most data are ultimately meaningless, and most interpretations wrong. But even the act of refuting the most absurd WAG is useful: it forces a reconsideration of the basic situation. So you can change the composition of the debaters, but they'll still be spouting crap most of the time.
Pros do lots of things well, but they don't have all the resources amateurs have. While pros must work systematically through a field, the amateur only works on the stuff s/he finds stimulating. When that "stimulating stuff" is not equal to "Working systematically through the field", the results are necessarily skewed, and the amateurs may not have the "big picture". But that's not necessarily bad. Any archaeologist commencing survey of an area knows that, in addition to lining up everybody for a grid-by-grid study, it helps to ask the locals if there's anything around they should know about.
What doesn't help is when someone makes an appeal to their own authority where a) that authority does not give them competence to speak on the case at hand, or b) how that authority gives them competence to speak on the case is not clear or specified, or c) they don't have the authority they claim for themselves.
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"
The Latin word for professional guild survives, although its scope has been reduced to only one institution: universitas