If the crew were having problems with the TANS, the first port of call would be SELECT DOPPLER
Perhaps their thought process was complicated by "So that's why it isn't cleared for use". Followed by "Is the Doppler cleared?". (No). "Is the GPS cleared"? (No). Easier just to list the avionics that were cleared for use. (None).
We just don't know, but that uncertainty is exactly what makes the verdict unsustainable. The fact that the clearance/release regulations were simply not implemented at that time compound the injustice.