I understand the sentiment behind the statement. And I would agree that the vast majority of courses, maybe even 90% should be playable for Granny. Certainly it holds true for Country Clubs where playability is so important. Yet there is also room for the occasional course that is designed for low handicappers without regard to players of lesser ability. I realize this may offend the democratic sensibilities of some. Nonetheless courses like PV, Royal County Down, or even my own club Musgrove Mill do not cater to my grandmother, God rest her soul.
That said, my wife, who is a grandmother enjoys RCD and MM even though she cannot possibly play anywhere near her handicap. But she is Norwegian and Norwegians like to suffer. That is why they settle in Minnesosta.