That seems like a fail-safe interpretation of communication: if there is no communication, stop the train. But that's a special case. GSM-R is much more than line authorities.
>GSM-R is a secure platform for voice and data communication between railway operational staff, including drivers, dispatchers, shunting team members, train engineers, and station controllers.
Designing the communication network itself in such a way that the entire thing can apparently fail, doesn't sound "fail-safe" to me. (Though its failure may trigger fail-safes in higher-level systems.) In particular, some functions may require communications to be "safe"; e.g., emergency personnel not being able to communicate is not "safe".
But perhaps this is being overstated in the vague reporting, and it's only a regional failure.
Interference led to the network stopping, not trains just racing towards each other due to bogus line authorities. That is, by definition, fail-safe