They only just started paying $15/hour recently, after the whole STOP-BEZOS Act back-and-forth with Bernie Sanders[1]. You appear to be implying they paid a $15/hour minimum wage before October of last year (you can't be a leader in something if you only started doing it 9 months ago because of overwhelming public pressure by politicians) -- they didn't.
My point is that low-wage workers are usually not in a position to quit one of their multiple jobs because they might become homeless or lose their health insurance. In fact, Amazon having higher wages means that low-wage workers are more likely to continue working there despite the conditions, because they have nowhere else they could go. But instead of discussing the point I was making, you are cherry-picking one particular phrase I used -- which applies to almost all other low-wage jobs but no longer (as of Oct 2018) applies to Amazon.
But also, the working conditions are the thing that most people have issue with (now that Amazon finally pays its workers a minimum wage that is reasonable). Not being able to take bathroom breaks without risking the loss of your job is not a humane way to treat people, even if you're paid $15/hour.
[1]: https://www.businessinsider.nl/bernie-sanders-amazon-fight-m...