The US in general is very conservative about allowing people sick leave, and Amazon in particular is notorious for making people work while sick. They were already running their operation right on the edge of the health of their employees, e.g.
https://www.vox.com/the-goods/2019/3/11/18260472/amazon-ware...The hard part isn't testing the workers. It's giving them sick pay for not coming in to work while sick.