I'm going to copy and paste from something I wrote in another thread.

From my experience with warehouses/fulfillment centers, all the other options are same or worse than Amazon with regards to worker treatment. Besides, on Amazon plenty of merchants do their own fulfillment, and those that do fulfill with Amazon are going to fulfill with Amazon on eBay or Rakuten or their own website anyway. To do so morally you'll have to look into the fulfillment details of any individual company you do business with.

Honestly, it just sucks to be an unskilled worker in today's society, its not something new to Amazon.