Actually, that was a 75 year old woman who misread the directions. In her case, it may not have been so much a cast iron stomach as it was a case of extremely low stomach acid that needed more acid.
I'm not convinced that you can manipulate the intestinal environment enough to create better absorption with the salt form. On one level, it seems like it should at least work a little bit, but then you're likely too have it all just flushed through. I think the mildness of the salt form is due to its ineffectiveness vs. the oil form.