The knock on Noblespirit is the same as that on NYstamps amd other similar outfits: they put on airs about being serious philatelists, but nothing could be further from the truth. They are either utterly clueless or completely predatory; they throw crap against the wall hoping that rubes will buy it. They prey upon the novice and the unknowledgeable. Cut from the same cloth as Posner, Anthony's, the late Bill Langs and Aldrich.
Point well taken, and Rog brings up a good example to illustrate your point.
To date, I've only thought of NS and similar eBay
types (NYstamps, etc) as purveyors of lower-end material - worldwide collections on Harris album pages, random box lots, etc. Wouldn't think of going to them for the high-end stuff.
I still maintain that there is an important and healthy market for these chepaer items, and such sellers play an active role in recirculating material that forms the basis of these types of collections.
There's a fine line in any hobby between specialized knowledge that comes from years of research and effort, and elitism - and we must remember a lot of folks have the interest but not necessarily the time or resources to dedicate to building up a pricey, specialized collection (and thus being a true 'philatelist' in the view of many).
With respect to the higher end material - the kind Rog linked to - I agree that these eBay
sellers are generally out of their depth, potentially willfully so. Happy (from the point of view of the seller) accidents ("we don't have time to research each high-end piece given the volume, so *shrug*) must happen all the time.
I suppose I never thought of these guys as high-end dealers, but putting myself in others' shoes...if I have more cash than experience and am looking to add (say) some Russian rarities to my collection, I'm going to get into trouble. And I see now how they might 'pass themselves off' as the real deal.
At the end of the day, it *is* up to the buyer to conduct their due diligence and understand the item they're shelling hundreds/thousands out for. But obviously the sellers are culpable here as well.