It obviously shouldn’t require some children getting toxic school supplies, people sustaining burns or worse from counterfeit 18650 lithium battery cells, or any other suffering to get testing and certification on certain products, but I don’t think it’s as bad as you imply by “passing the buck”. It’s the easy way out for Amazon, sure, but if they do it enough times they will get a reputation for spotty inventory.

I’ve already experienced this a few times with certain classes of products they wouldn’t ship to California due to stricter regulation on how much ozone they produce. That’s why I had to go to Bed Bath & Beyond to buy a HEPA air filter for my bedroom during the fires last year: https://ww3.arb.ca.gov/research/indoor/ozone.htm

When it’s one product it’s easy to point fingers at the regulation for the inconvenience, but shouldn’t I be glad my filter fits those tighter regulations? The diesel car maker scandal is proof regulations can be cheated, but it seems to me like more regulation would get us to a point where that would be quickly exposed.

Let Amazon pass the buck to sellers. Regulate more things, and eventually it will be in their economic interest to run their own tests. They got where they were by having everything, and they can fall if that reputation does.