As you can see in the excerpt above, it mentions specifically NDB, TACAN and VOR approaches and that monitoring is recommended, but not required.
If an NDB DME approach for example requires a DME that is co-located with an ILS i cannot use that nav aid for technical reasons as i can not use any ILS frequency when flying an NDB approach, the approach mode would try to fly the ILS instead of the NDB approach. However it is still legal to fly the approach without monitoring that DME as long as i have two FMC and 2 GPS.
In theory the nav aid needed for the approach must be working, however if i'm not monitoring that nav aid it becomes a theoretical issue as i won't see if it becomes inop during the approach.