It seems to me that it could be a product of how the shrimp are raised... thus, how they adapt.
I have seen one European person who uses Zero Water for their tanks... another that uses bottled water with nothing added. Neither have high tech tanks, if I recall right.
Then we have Australia.... even with shrimp such as crystals, get a buffering substrate, throw in tap and you're good! Or maybe not use a buffering substrate at all? Not sure...
In short, shrimp keeping can vary around the world. The only thing I know for sure is that it would be great to get away from "tap water is fine for shrimp" bull. It's great if tap works for you! But recommending that to someone who may have completely different parameters than you, parameters that aren't ideal for shrimp, only sets that person up for failure and who knows how many lives of shrimp.