Words like "corrupt" have pretty specific meanings. Amazon doesn't rise to that level, not even close. Even "bad" is a very debatable thing - obviously its customers don't think so.

Unions that are outright threatening or bribing people to break a vote, though. That's an unambiguous use of the word corruption.

The difference is that amazon is driving innovation which enables you to stay competitive. Unions cause stagnation which will lead to being outcompeted in the long term, even if you could argue a more peaceful existence in the short/medium term, you are just putting on blinders.