I worked on the film, so you might assume I have biases towards it and the subject. As for the terms of your critique, bombastic is to subjective to debate; you find it bombastic, ... ok. Alarmist suggests that the problem is not real. The term contradictory seems to be added for the sake of the magic number 3 - you point out no actual contradictions presented by the film.
The book, Blue Gold: The Fight to Stop the Corporate Theft of the World's Water, is not a scientific work in and of itself but a general review of such science juxtaposed with corporate maleficence with the issue and the growing trend to privatize this diminishing resource. The subject is a relatively unknown yet an imminent world wide crisis. It should make your head spin.
For a taste of some science not covered in the film, the USGS measured a 1 foot drop in the Ogallala aquifer between 2003 and 2007. It is estimated to have about 20-25 years left. The Ogallala supplies a bit over a quarter of the agriculture in the US; the great plains, the bread basket. Other parts of the world are worse off, others better.
As far as government vs private management, the government has, or should have, different motivations for provided services than a non-municipal or for profit corporation - profit vs public interest. Did you like Enron; do you like the financial crisis that we're going through now? You'll love privatized water.
This film isn't about "Hey man, I made a Great film, give me an Oscar." It is about, "WAKE THE f--- UP!"