Anatomy of a leak: how iPhones spill the ID of networks they access

iPhones expose the unique identifiers of recently accessed wireless routers. What possible justification does Apple have for building this leakage capability into its entire line of wireless products when smartphones, laptops, and tablets from competitors don't? And how is it that Google, Wigle.net, and others get away with publishing the MAC addresses of millions of wireless access devices and their precise geographic location?