Feudalism was a hierarchical system. Not all nobles went around hacking off heads - they could farm that out to higher ups who kept order. What's the difference between Amazon's reliance on national governments? The business model only works because the US enforces peace on parts of the world and because the Chinese government allows its workers to be used for pennies on the dollar. Within Amazon's kingdom, good luck getting the authorities to help you if you aren't a big player.
Meanwhile the average worker who isn't any less intelligent or hard working is seen as worth a fraction of a percentage of Bezos. Sounds like feudalism, serfdom, slavery, or whatever you'd like to call it. That we can celebrate such disparities of human value and even worse in some places this kind of rampant greed is seen as something good is what is truly terrifying.