Why you shouldn't use soap to clean a pizza stone? or some pans and pots? I was reading answers to this question How do I season my new pizza stone? and many people advised not to use soap on a pizza stone, I don't have a pizza stone but I have read similar advice for some pots and pans,  

My question is why you can't use soap to clean this stuff, is it just unnecessary (because a pizza stone is always in the oven and every thing on it will burn) or there is a reason NOT to do it?
Some cookware are 'cured'. Mostly cast iron pots and pans. I never heard of a pizza stone being cured, so I'm guessing this is to avoid eating soap. Other than that, I wouldn't know.

Cast iron gets cured for two reasons: 1. Create a non-stick layer 2. Avoid oxidation. Neither of these reasons apply to stones (or do they?)