Because you don't have to apply for a trademark to have it legally protected. It helps, sure, but it isn't required. If the report is true, and iCloud has been operating under that name since 2005, then Apple is in the wrong.

That said, there is an argument to be made that iAnything means Apple. Legally, it would be impossible to enforce, but culturally, it's very much the case.

Nor shall we forget the all important: Amendment X The powers not delegated to the United States by the Constitution, nor prohibited by it to the states, are reserved to the states respectively, or to the people. If the people want the right of privacy, that power is granted to them.