Earlier quoted context omitted.
And most importantly they have only one listing for the same item. In Amazon and Walmart you have multiple listings of the same product by different sellers at different prices. In Amazon it's really annoying to see several pages of basically the same product.
Amazon tries to coalesce these pages together in a single product-detail page with multiple offers. Sellers frequently try to avoid this coalescing (because otherwise, they're only competing on price). This could be as simple as pad printing a meaningless 5-6 character brand onto the product [making it technically different] or by making the description slightly different.
My favorite was a handheld coffee grinder. The item was unbranded, and the manual had some brand name manually scratched out with an inkpen everywhere it was mentioned. It's actually a nice coffee grinder, believe it or not.