I'm no fan of Amazon, but it's the third most valuable company on the planet. Whatever they're doing is obviously working for them, even if I personally wouldn't want to work there.
I used to think along the same lines, but morality and economic success are different things. Sometimes a few 'things' they do, moral or not, are the deciding factor to reach such high valuations, and then we fixate over things like the '?' email and try to explain it as 'the secret' management technique or whatever that made them successful, when in reality they were successful in spite of it not because of it.