Amazon warehouse jobs aren't just physically demanding. I agree that one can study hard after half a day spent on some physical effort. Instead the problem is that Amazon pickers are under constant stress all those hours to meet targets far more demanding than most other jobs. I would expect that constant mental stress to leave people so frazzled at day's end that they would be unable to hit the books and concentrate.
And you've just made my point for me. "Most" other jobs. It's not the most difficult, most physical, most dangerous. Where are the people saying people in job "X" can't possibly study after a day at work? Somehow, that reasoning is confined to warehouse workers.
