JME,
If I construed PM's description correctly (at a par of 70 it is unrelenting[for members certainly]), I beleive he's referring to the two (2) par-changed holes (#9 and #16).
When those holes are played as par 5s by members (or me, occasionally
) they are a bit of break, a place to re-trench with relation to the scorecard. Of course, this is just on the psychology of a medal round to par...but 9 and 16 are indeed the easiest pars on the course when they are 5s. The ability to achieve a par score on a course when missed greens and three putt doubles are everywhere, it is a place where the course "relents" and permits "success" - maybe gives a (gulp) birdie to the average player. When you are playing them as 4s, and your "birdie" is now just a saved par and your 5 is another "bogey" the pressure takes on an unrelenting nature.
This idea might be true anywhere where a par is changed downward, but at WFW, the position of those holes is crucial to what PM is referencing...
#9, besides being the totaling key of your front side, comes nearly in the middle of the "easiest stretch" of the course...5-12, but is bracketed by two fiercely challenging holes, the wildly underrated 8th "Arena" and the famous par 3 10th "Pulpit". If #9 is made into a 4 (again this is just psychological - you're total is your total) then the easiest stretch of the course no longer exists...it becomes JUST 5,6 and 7....if you don't make hay there, your medal round isn't going to be very good.
On the other end of the round, 16 (as a card 5) breaks up maybe the hardest stretch of Par 4s known in Golf...when 16 is a 460-480 yard "4" it means you close with five par 4s, 390, 410, 470, 440, 430 (members tees), all with difficult, well-defended greens, probably the least-birdied stretch of 5.
It is, to use the catch word, "unrelenting." When 9 and 16 are Par 5s and the course thus played at level-fours 72, there is an resemblance to an oasis at those points.
cheers
vk