I'm going to go on a limb here, but I think the point that Frank is trying to make is that the best way to set up a planted aquarium is by promoting the entire ecological system that emphasizes the establishment and use of microorganisms.
All of the ADA products that he uses are mainly for trying to get the microorganisms established in order to help (1) filter the water, (2) establish plant growth and (3) fight algae.
In his previous post, Frank commented that people are too caught up with the "what" to buy and not "why" you should buy it. In a nutshell, he's saying that you should buy or use items (and techniques) that will help to establish the microorganisms in the aquarium. Is it possible to set up an aquarium without the use of the specific (ADA) items he suggests / uses? Yes... but if you do so, then the chances of having the wrong microorganisms or algae establish themselves is greater, leading to more problems than you want.
As an example, he mentions eco-complete; you can certainly grow plants in it (nobody is disputing that fact), but eco-complete is not as ideal a substrate for the promotion and development of microorganisms (in comparison to Aqua soil... or Aqua soil + Power sand... or esp. Aqua soil + Power Sand + other additives).
To me the root of the problem in this "discussion" is that most people haven't used or evaluated the entire ADA line. Why would that be important? Because this entire thread is supposed to be an avenue as to the *BEST* way to grow aquatic plants, not whatever method works. As Frank has said before - there are lots of ways to set up a planted aquarium and be successful with it. However, has everyone who has commented here set up an aquarium using the ADA method and products versus using another method and products? I highly doubt it. There's a big difference between saying "this method works" and "this (other) method is the best", esp. when you haven't even used the (other) method.
Here's an analogy of how *I* think of the ADA method versus the other methods (let's use EI dosing as an example). The ADA Method is the equivalent of Organic Lawn Care and EI dosing is the equivalent of Conventional Lawn Care. Both methods will give you a nice green lawn, but the Organic Lawn Care system is a better method. (If you don't understand this analogy, I would highly suggest reading the book "Teaming with Microbes" by Jeff Lowenfels and Wayne Lewis - It will change the way you view organic techniques and conventional fertilizers and methods...)