To expect someone else to be held responsible because the authorities are not doing their job adequately is, IMO, not appropriate
Why do we not operate on the same principle with illegal drugs, smuggled tobacco and alcohol etc?
I think we do. I can't imagine that anyone 'further down the chain' would be prosecuted for the illegal import (by someone else) of drugs, tobacco or alcohol.
No - that wasn't what I was saying.
We don't hold people further down the supply chain responsible for
importation, but we do subject them to sanctions for selling whatever makes it through the importation interdictions. Nor do we exempt people at any point in the supply chain within our jurisdiction just because in the jurisdiction where the items/substances are manufactured the authorities do not prevent their manufacture.
Accountable for what - see above.
Accountable for facilitating the sale, through/on a UK website to a UK customer. However you want to define "facilitating" (short of "what-ifs" so obviously ridiculous that they could only be put forward by someone fundamentally opposed to the idea of any legislation aimed at protecting the unintelligent/naive/trusting from being exploited by the venal) then yes I hold to the view that they should, and must, be held accountable.
It cannot be thought, by anybody with an IQ bigger than their shoe size, that when Amazon.co.uk or .fr or .de provide,
for profit, web hosting, shopping cart, payment, search, review, customer accounts, warehousing, packaging, shipment etc etc etc facilities for Lucky Boy Electrics in Guandong that they are not facilitating sales by Lucky Boy Electrics into the UK, or France or Germany.
Previous extrapolations of "facilitating" have included credit card providers. Well, why not? If China will not put a stop to their own citizens lying, cheating, defrauding, and exporting danger then why not? Mastercard and Visa will not abandon the UK, or Europe, if they are threatened with sanctions. When the Wikileaks exposé broke they pro-actively started refusing to process payments to Wikileaks just out of
fear of sanctions. If they were faced with being drawn into a mess created because Amazon refused to police their business customers they would not abandon the UK, or Europe, with all its restaurants and supermarkets, and department stores and hotels and airlines and travel companies and railways and clothes shops and petrol stations and... and... and...
They would drop Amazon like a stinking maggot-laden corpse.
And as I have said before - Amazon would suddenly find that they could do something after all. At the moment they have no incentive to do so. They will never start acting like responsible, conscientious, upright people until they are forced to under pain of penalties which they cannot write off as a cost of doing business.