comments I haven't verified state that the people had a welfare state income keeping them alive, and that by merely extending an offer of work - at any salary - Amazon causes that to be revoked.

This isn't literally "initiating force" but if it is true then it is very similar in effect to the mugging scenario, and having the mugger use unseen but still present power to "make an offer you can't refuse" is still not a fair and ethical way to egg people to voluntarily enter into contracts.