PADI's dive depth standards - Vague?

[Thalassamania]

There are viable physiological reasons to not go below 40M - 132' as have already been discussed. This is why it is a "hard bottom" for several agencies and resorts plus what I have read the US Navy as well.

No, there is no physiological reason for 130. As stated earlier, it comes from a U.S. Navy operational decision to shift to SSA at that depth.

 

[Steve R]

The PADI training seems to encourage stepped exposures to deeper depths as training, experience and personal comfort level dictate....

Uhmmm. No, it just might look that way to the casual observer.

Unless of course you believe that a diver with less than a dozen dives is in any way shape or form likely to be experienced or trained well enough to be at 100ft within any system, generally speaking.

Safety has to be encouraged and gradual exposure to deeper dives in a controlled training environment is a good way of acclimatizing people.

I do agree with you here, but unfortunately this rarely, if ever, happens in mainstream recreational instruction. In fact, by some designs, it is actively discouraged for profit's sake alone.