I am not sure where to start on this one, but I'll give my .02 for what it is worth.
The 20+ handicappers that I know generally have one thing on their mind, making contact with the ball. Flight trajectory, flight pattern, carry distances, firmness of the ground, etc, etc. really have little bearing on him before a shot. He just wants to hit the ball solid hopefully aiming toward his target. That is a good shot in his repertoire of shots.
The difference with a scratch player or better is that their repertoire of shots is soooooooo much greater. They may not always execute the shot correctly, but they generally know and attempt the proper shot for most situations whereas the 20+ handicappers is just back there trying to make contact with ball.
Thus, the scratch player wants to "have a shot", at least some shot, under almost all circumstances. Of course, that isn't going to happen and they have to "take their medicine for a bad shot" and just play to make a bogey, rather than a par. The same situation for a 20+ handicapper generally creates a situation where they can't even finish the hole a lot of the time. Not enough "repertoire" of shots for tough situations.
Scratch play GCA's have a much better comprehension of what the ball does when it comes in contact with the ground, and what the 'possibilities" of success are with any given shot. The 20+ handicapper gca, is just back there hoping to hit the ball on the green somewhere, anywhere. So when it comes to design, they can't have the same ability to design "degree of difficulty" to shots, because they are all difficult to the 20+ handicapper.
Therefore, I have no idea how a 20+ handicapper can realistically have any comprehension of the rating category "resistance to scoring". I think that is why you often find 20+ gca's either designing course much too difficult or much too easy. They don't get it, because they have never experienced it. They can excel in every other category, and often make up for their lack of understanding in the RTS category, by excelling in the other categories.
I have no problem with that approach, but in this particular thread, there is a differentiation, imho.