To me, glory holes have a lot of the same characteristics of the hunting scenes I saw as a kid. From sitting in a dark fish house waiting for a muskie to swim by, to sitting in a fish or duck boat, the video booth or bathroom stall was the same scenario...

Sitting there waiting for the anonymous catch to come into striking range, preceded by the watching, waiting, baiting and courting.

Maybe some of the thrill was the actual getting the cock that came though the hole, but that was the conclusion of the longer process - all resembling the ingrained trait of the past 100,000s of years in our DNA of: hunting.