I don't think that anyone is suggesting that only folks who are fortunate enough to have owned pretty much everything are qualified to comment. What people are saying is that when folks feel compelled to comment on gear that they haven't heard, it's typically of no value and tends to clog up the forums.
As I had said, this has been going on forever. For example, back in the good old days, anytime anyone was looking to purchase an amp, a handful of folks would invariably chime in that they should get a DIY Meta42. Said that it was the greatest thing ever, and that spending money on anything else (especially something by - gasp! - HeadRoom) was just a waste. Setting aside for a moment that money spent on an amp from an established manufacturer might have its own benefits, what invariably ended up happening is that at least half of the people who recommended the Meta42 had NEVER EVEN HEARD either the Meta42 or the amp that they were saying was such a waste of money.
I think a big part of this is a certain Flavor of the Month sort of groupthink amongs members in general, but particularly (no offense intended) newer/less experienced members. It has been and remains a mystery why people feel compelled to do this. It's not a crime to be limited in your experiences...is hearing the sound of one's own (written) voice so important?
* For the record, I heard a lot of different Meta42's back in the day, and if you had a good builder it was a pretty good amp.