I find that to be some wearisome reasoning myself. If you can cope with technology above the surface it should not be that problematic below the surface. Why not just say, in our style of diving, at the tech level, we don't use that tool (because there it is not a safe practice) and, because we believe in continuity, we don't use it at the rec level either.. without stretching credulity by inventing reasons.
This is the big disconnect that rec divers feel when viewing dir. They see that rec diving can be done safely, differently, so the rigid stance doesn't make sense... unless you understand the philosophy of beginning with the end in mind and the continuity that it creates. Other choices at the rec level, while perfectly sound in themselves, don't "fit" further down the spectrum so they are not adopted. It really is as easy as that. If you get it, you'll get almost all the decisions revolving around the system.
The problem with that BAUE list is that 99% of rec divers today are using computers relatively safely so that, without the real reasoning explained, the reader is drawn towards two conclusions:
1.) dir divers are too inept to safely use what most other people use.
2.) Someone is making far fetched stuff up to justify a position.
I personally appreciate the singleness of purpose that dir adopts in the sense of maintaining focus on the primary goal of the system: Creating a seamless group of divers that can interact and move from one end of the spectrum to the other. Anything that takes away from that concept is put aside for the greater good; the whole is more valuable than the sum of its parts. I think that is good enough to use as justification without painting those parts as wrong.
