Hi Matt,
Sorry mate I do not agree with you.

There are areas such as in Mexico where the caves are quite shallow and the procedures and techniques of technical diving in terms of deep diving do not apply at most of the diving is done here.
Yes for the most part the coastal caves of Quintana Roo are relatively shallow but long dive times still incurr deco penalties.
I personally do many dives here that require deco and so do many others.

As for the rest of Mexico I think there may be one or 2 deep caves that may require a little bit of deco to dive

During training lectures and discussion is included in the area of decompression diving but actual decompression dives are not done, or seldom done.
I include a decompression dive in all my full cave classes
I also know that other Instructors do as well
In my personal opinion as well as the lecture / discussion you actually have to get in the water and put the theory into practice
In fact I am going to Naharon tomorrow to complete the Deco dive for the cave class I am currently teaching