So what, even if Amazon pays slightly above a minimum living wage, the working conditions are extremely bad (e.g. no adequate toilets, extremely long walking times towards the break room, drivers being forced to piss in bottles, employees being pitted against each other by a relentless algorithm without respect for differences in age, body strength or whatever).

Given that the social security system in the US (and to be fair, even in Europe) is pretty lacking and Amazon (as well as Walmart) is setting up shop exclusively in areas with high unemployment, it can very well be said that people have the free choice to work at Amazon instead of another employer that treats their workers better, so yes it is perfectly valid to call it "de facto indentured servitude".