In my mind, he is mixing up two distinct ideas, both of which I agree with.
First, build some greens at ground level, generally following the basic contour
Two- even when building up greens, some should have drastic contours, others gentle contours.
As to the second, I try to draw my sets of green details with a mix of basic slopes from 1.75% to 2.5% thinking golfers might never quite be able to get the read on subtle differences in slope. I can't really quantify that, but figure it doesn't hurt.
I also might build up a green, but then rather than have gentle rolls throughout, create what I call a "constant plane" green, which isn't flat (they all have to slope some) but has absolutely no internal contour. These seem to work well on gently uphill holes where even a small nob can block the vision to everything behind it. This type of green doesn't have to be at ground level.
For that matter, I think golfers do notice when greens are set at varying levels from zero to say 10 feet or more above the fairway level, as well as the slope of the entrance from fairway to green. (esp. seniors who use that slope to roll shots on the green)