The Hurt report was perhaps useful at one time. It is no longer as useful. Or IMO, much use at all. This is one of the reasons the AMA is pushing so hard for some federal funding for a new motorcycle safety study. The motorcycling environment has changed remarkably in 30 years. The data may very well have changed as well. For one thing, a "middleweight" sportbike today has significantly more peak horsepower than the largest open-class machine when the Hurt report was developed. Heck, a middleweight streetbike today has more peak horsepower than most racebikes of that era. (and also has better tires, suspension, electronics, and every other component as well, of course)
Bolded part isn't supported by any statistics I've ever read or even heard talked about. Other than in the editorial that served as the initial topic for this thread, where it was postulated that displacement for sportbikes wasn't the key indicator of crashes in a controlled study of experienced riders, because nobody crashed.