> If the manufacturers are not held accountable

How does a customer of a retailer hold a manufacturer accountable when they have no relationship with said manufacturer?

> But most of the time, retailers are just selling products they think customers will want to buy.

I don't think retailers are nearly as helpless or unwitting as that. Amazon definitely know they have unsafe products on the shelves no matter how dumb they may play.

> The retailers are the front line for returns as that's the point of contact for the customer

They're also the front line for consumer safety reporting, by law. All companies (not only retailers, actually) have a statutory duty to report unsafe consumer goods, even in the US, and not only for CPC/GCC certified goods. When a customer reports an unsafe product to their retailer, the retailer should forward this information, along with batch codes, origins, sourcing information etc (which the customer obviously will not know). This is the early-warning system that leads to things like recalls, withdrawals and so on, before something causes widespread harm.