I've worked in shipping for a couple months and I can only say this: People should order way less stuff online or make sure they are using an ethical shipping company (if they even exist).
the industry prays on young people (often minorities) who have trouble getting other jobs. they almost exclusively hire people with short term contracts (because your body can't take the work for more than a few months). I've been part of a union for a long time and I know a lot about work safety. These companies teach people nothing and they can only meet their deadlines if people actively break their backs twisting around, doing unsafe lifts and generally working to fast.
I get that shipping is sometimes necessary, but it can only be as fast and cheap as it is, because poor people pay with their bodies.