The UK has social safety nets that Americans don't get when they have a job. Amazon isn't allowed to play the same game in countries with worker protections.
I can certainly believe there are issues for Amazon workers in the US that don’t apply in the UK to the same degree. Although Amazon does seem to have various heath insurance plans for US workers. I assume workers have to pay some amount in as is the case with most jobs, including white collar ones, in the US.
