dominating the market and holding a monopoly are not the same thing. Amazon has a dominant position in many markets, but are not a monopoly on any market unless you re-define the market to be amazon's portion of it.

Does amazon have a retail monopoly? absolutely not. An online retail monopoly? still no. An online book selling monopoly? okay, now we're getting closer but still not a monopoly. A kindle books monopoly? yeah, by definition.