What makes the Warwick Hills golf course (where the current buick open is being played) so easy?

I just read that the Warwick hills golf course , home of the buick open this year, is one of the easiest courses on the PGA tour, with an average winning score of 21 under par. What makes it so easy?? It is by no means short in length considering the fact that it is well over 7000 yards long. .Any players or ideas??|||Wide, rolling fairways, receptive greens and ideal scoring conditions. Mid 70's temp wise today and yesterday with very little wind. Now remember these guys aren't 10 handicaps either!|||Wide, rolling fairways, receptive greens and ideal scoring conditions. Mid 70's temp wise today and yesterday with very little wind. Now remember these guys aren't 10 handicaps either!