I enjoyed reading this - for various reasons - but I will start off by saying that I know a number of divers who started off on the DIR route and have long since abandoned it as mostly, male cow poop.
My beef with the DIR posse has always been that those who believe they are Doing It Right treat their philosophy as if it were gospel and therefore all other diving that is not DIR must logically be Doing It Wrong. The analogy between DIR diving and religion is apt - we have the right faith, and everybody else is to be condemned as unrighteous and unworthy, and we must convert them to our way of thinking.
There are some types of diving where certain techniques, equipment configurations and gas mixtures are not only correct, but essential - and that's great. Diving though deep caves where the margin for error is so much slimmer than floating about with the fish in warm tropical water requires a great deal more control and just like a cave diver would be horrified if an AOW certified diver on a single air tank tried to do what they do - I also have to admit to a loud underwater guffaw when I see DIR-style divers attempting a basic tropical recreational dive all fully geared out in what is next-to-useless equipment.
Like any activity, the only way you can Do It Right is to take the best advice from as many different sources as you can, learn from your experiences, and figure out what is Right For You. Proselytising egomaniacs serve only themselves.
pfft pfft my two bar
C.