Thanks for bringing this up. I want Amazon to take better care of employees precisely because I have money invested in them; because I believe in a knowledge economy, the greatest asset a company has is its people, and in the long-term this will matter. Amazon can be a lot more valuable, if employees can build long-term careers there and are better cared for.
I am rational. I want my money to work hard for my family. If I believe, I can provide a secure future for my family by investing in AMZN then I will do that. Through all the mutual/index funds, I am probably invested in a lot of companies whose practices I disagree with. Examples: Avoiding taxes (double irish with a dutch sandwich), super low minimum wages and expecting public to pay for their care (walmart and food stamps use of their employees), abysmal working conditions (foxconn deaths/suicides), shipping manufacturing jobs to China/Malaysia/Philippines and exploiting low-wage workers there, advertising and selling unhealthy/processed and getting kids hooked to high-{sugar,salt,bad fat} diet. We have practically proved that the best engine to create wealth is capitalism. The dichotomy you have provided is a false one. I love all the good properties of capitalism but I am also aware of its acute shortcomings, if there is no government or regulation. This doesn't mean that I will stop being a rational economic actor.
Things I mentioned are what I heard from current/ex Amazon employees. What I wrote about benefits are facts (else people would have refuted them right away). Only exaggeration was about Execs laughing their asses off; I was just making a point.