not something I've ever noticed either (only speaking for RB, I don't use any other bike forums, or have FB , etc). Large collections can be defined in differnet ways - some people have loads of bikes but individual value can be low, others may have only 1 or 2 that are each worth more than several "basic" models.
I like seeing some of the large collections, both in numbers of bikes and models, as it's the only way I'll ever get to see some of those bikes, and I'm glad to see them being cared for and looked after, even ridden in some cases but I don't mind if they're not. I think potentially with a large collection comes a large knowledge base (probably, but not always), and can see how quite possibly those with large collections could have greater knowledge and understanding over those of us that have only built a few bikes, but that's not a given either.
Pointing out "errors" in builds I think is fine, so long as it is done the right way - I'll admit to doing it myself, but hopefully I did it in a constructive or helpful way! It's very easy for even the best bike builder in the work to miss a detail or two!