It is odd to me that every website from slice on up to American kitchens say that stones absorb moisture. Would be cool to weigh them hot and and after use. But I ain't going to do it.
I am not sure if it is "every" website. Certainly, not the website from the manufacturer of baking stones that makes Fibrament (quoted above). Regardless, would you please provide the links to America Test Kitchens and Slice? I subscribe to Cooks Illustrated and I read the article on baking stones. The only transference that I saw discussed was heat transference, not water. For example, Cooks Illustrated said: "Baking stones simulate a brick oven in your home oven, absorbing and radiating intense, consistent heat to produce crisp, golden-brown pizza, calzones, and bread. "
Pizza stones are porous, so they do absorb moisture at room temperature and thereabouts. But, the situation at hand is when you are baking a pizza (or bread, etc.) on a stone that has been preheated to several hundred degrees, way over boiling point. And the oven is at that temperature. A 500 degree stone absorbing water seems to be a phenomenon not supported by the laws of physics (even if some random food blogger made a statement).
Moisture may be rapidly leaving the dough. More rapidly than otherwise with a stone. But, this is not the same as the stone absorbing the moisture.
I do not understand why you find it "odd" and have difficulty accepting this logic.