The fact that all of those players were in college makes them above average to begin with. Show me the D&D groups made up of high school dropouts.
The people I knew in college who watched sports were also in college...
Also, attending college does not guarantee that one is above average intelligence. The average intelligence of college attendees is higher than the average intelligence of all adults, but there are certainly some college attendees with below-average intelligence.
Really? What do you base that claim on? The fact that lots of "geeky" people play D&D doesn't mean that the average person playing D&D is actually smarter than the average sports fan. In college I knew some smart people who played D&D, but I knew some dumb people who played it, too.