Playing devil's advocate, how does the engine size make a bike more or less dangerous? A R1 is not a beginner's bike but neither is a R6. If you don't know how to countersteer and keep the bike under control, it doesn't matter what type of bike you are on, you are going to go down.
Generally, it was the acceleration that caught them out, going too fast for the corner according to accident reports. Passing a test on a Honda 500 didn't quite prepare them for that!