My experience has been that the people selling such rubbish are severely clue-deficient, and take the labelling on trust, which as often as not never mentions SMB version support. SMB is SMB is SMB.
So it's a combination of piss-poor documentation from the manufacturer, and low-paid sales staff.
For most of this century the well-informed salesman has been a dying breed, but at least I can download the manuals. But does that help?
Last week I was working on an old Dell workstation, it is good kit and I got a good deal. But the manual (and Dell support) are inadequate on how to fit anything in the front-of-case drive bays. Problem sorted, but it doesn't impress.