A bit misleading.... He also states, in the same place, that you should age and aerate such water for no less than 1 week. How many people are willing to do that? Also states that corals and sensitive inverts still demand purified water.
I have not read his new edition of the book and will have to send him an e-mail and ask for his reasoning. While I agree that there are many water sources that are safe to use, it varies from place to place. Like I said, I had no problems when I lived in Michigan and used tap for years. When I first moved to Cobb county in the early 2000s, it became a HUGE problem. I did not see why until I looked at the water testing reports put out by the county. Lawrenceville city water was much better but I still would not risk it. RO water is cheap to make and removes much of the stuff (copper and PO4 namely) that was found in too high of a level for my liking. Maybe, by aerating the water for a week you allow of stuff in the city water to be removed (CL, Floride, PO4, NO3, etc) but I would want to see that put to the test.
While it may be ok out of the presence of coral and sensitive inverts, if someone has had a problem with algae in the past that is driving them from the hobby, I do not think that I would go with any less than RO water. But that is my opinion. Take it for what it is worth.