Hmm, I’ve seen quite a few warehouses and they’ve mostly been clean, decent places to work. Not the highest skill or wage work, but certainly not terrible or cruel. But, they weren’t major shipping depots for Amazon either. Mostly small/mid-sized.
In one, a subcontractor doing installations for DTV, the warehouse staff workload was pretty light. Sure, they’d hump a bit in the morning and evening to the installers checked out and back in, but the rest of the day was light.
Certainly no overtime. And CALOSHA is quite strict in their rules. I don’t recall a single injury in the warehouse.
Now the installers generally worked quite hard - the good ones completing installations 3-4 per day.
The workloads vary by time and domain. Amazon has huge volume, huge peaks, and everything is an individual item. The work environment has to be crazy to keep up to the goal.
I think the closest I have seen is the office supply chain. When you buy a notebook in a shop like office depot, there is a warehouse upstream that can the same order, it will package the notebook and deliver it the next day to the shop to refill. It's similar to Amazon in that they deliver small items of minimal value, one by one.
Bulk warehouses and specialized products should have better conditions because they can have higher margin and/or less units of volume to manage.