I live in Tennessee, too. I've only ridden the dragon a handful of times, all during the week when the traffic is pretty thin. The Dragon is a great road that does command the rider's respect and, above all, constant attention.
Most (though not all) of these accidents happen on the weekends when the Dragon is very crowded. Some of these crashes are less experienced riders who typically show up on the weekend when their limited skill set gets challenged by both the road and the traffic. Some of these crashes are the result of some folks who want to ride the Dragon hard. When the dragon is not so crowded -- weekdays -- they take themselves out, maybe a riding buddy, too. On the weekends and in the crowds, things get a bit more dicey and sometimes, unfortunately, one (or more) totally innocent rider(s) is(are) involved.
I'm sure there are other causes for accidents such as mechanical failure. Truth be told, though, on a road like the Dragon, most of the accidents can be chalked up to bad judgement on someone's part.