The article makes no mention of the fact that the Siri app was free. What possible obligation does Apple have to continue to provide a service to "customers", when these users have not bought any product or service, and Apple itself didn't even own the app when the service began.

Lots of people seem to think that we have a right to continued access to free web apps/services just because once something is given it can't be taken away; this obviously isn't true. This particular case is just Apple being a business and isn't even particularly egregious.