Because it is 2012, and every networked digital system in the world uses IP, and every business in the world has an Internet connection the same way every business in the world has a phone. Incidentally: there is nothing new under the sun: these same critical systems used to be exposed via the phone network.

I don't know what they're saying, but yes, I assure you, there is crazy stuff that is one or two pivot hosts away from an Internet attacker.