Agreed. It's most likely a sin of omission, creating a broken system because it's not in their interests to fix the general counterfeiting problem.
There may be ancillary benefits, like increased seller competition into their monopsony, but it's not a priority for them to fix, because apparently it doesn't affect their bottom line enough.
It's not like it's hard to come up with a solution to the problem - they have lots of ways of surfacing prime-eligible items, you could have a similar way of surfacing manufacturer-approved resellers for some items. And as others have mentioned, there are no counterfeit kindles on amazon.com
> it's not in their interests to fix the general counterfeiting problem
But really it is, because judging on comments here, people are looking at aliexpress when they don't care that they are buying a cheap chinese product.
If Amazon is known as the place where you pay for a brand and get a counterfeit, and aliexpress is where you can just pay less for the counterfeit, that seems to me like a problem Amazon would want to fix.