He may have said that (not sure), But he’s not prescribing it:
See here:
For example, Dec 1 ride. Not intervals. Well, one giant interval at LT1.
ISM Zone 2 is low tempo, It’s not all he prescribes. It’s not general endurance riding (like many of the examples in this thread of “look I did Zone 2”). Not sure how else to clear up the confusion over Z2.