Without the incorrect TAT reading the engine would not have caused its own damage to itself
OK, now I understand the statement. It's inherently wrong, but I understand....
The engine control has multiple inputs of TAT. It gets the aircraft values of TAT, but it's primary indication is via an inlet mounted temperature probe. During 'normal' operation, the engine will use the aircraft TAT value (assuming it agrees - within a tolerance - of the engine probe). That way, minor differences in sensor tolerances won't result in cross-wing differences in engine operation.
But, if there is a significant difference between aircraft and engine sensors, the engine control will default to the engine sensors. The unheated dedicated engine temp sensor is not susceptible to ice crystal icing (pretty much, by definition, ice crystals will not accrete on sub-freezing surfaces - they just bounce off). So as soon as aircraft TAT was corrupted by ice crystal icing, the engine controls reverted to their dedicated sensors which were not significantly affected by ice crystals.
The engine damage was not cause by corrupted aircraft TAT measurements because the engine control wouldn't have used it.
Readers Digest version - we design for this.