Regular oil is full of sulfur. When a car is driven short distances and doesn't warm up enough to evaporate the condensate the water combines with the sulfur and makes sulfuric acid.
No, it's not. About the only oil I can recall using sulphur in any significant quantity in its formulation is Royal Purple's old Synerlec product, which is what coined the nickname "Royal Sulphur", as it (Synerlec) was a sulphated ester.
Sulphur that finds its way into the sump is due to the process of combustion and gets there as a result of blow-by. This is why oils are highly based with components like calcium, which neutralize the acids produced so that they don't cause damage. This is measured by way of TBN in used oil analysis. We also measure TAN, which is Total Acid Number. This can be skewed by formula however, which is why looking at remaining TBN is important.