Anyone working over their contracted hours needs to realise they're being exploited by their employer. Sometimes this is justified: we pay more than the going rate because we expect you to step up occasionally. Maybe it's kind of expected with Amazon in particular.
But when it descends into perma death march and your manager flings you "a few" days holiday in recompense... does that make up for it? If it doesn't, to whom has the profit gone?
They have a contract, but the contract will specify them as "exempt salaried" employees. That's pretty standard across the board in the tech world (as well as many other professional roles).
Exempt salaried employees aren't paid by the hour, and don't have a set number of hours they are expected to work. There is no overtime, but there's also no (contractual) penalty for working fewer than 40 hours in a week.
But when it descends into perma death march and your manager flings you "a few" days holiday in recompense... does that make up for it? If it doesn't, to whom has the profit gone?