A super sport of any sort is much more difficult to operate than the 250 or 300 is. Yes, while you are always in control up until the crash site of any bike, a super sport is much easier to make an unrecoverable mistake on. Even the R6 which is regarded as the gutless wonder of super sports below 10k RPMs can get you into serious trouble if you mess up. The quickly revving nature of the engine mixed with the much more sensitive and tuned throttle has bit many newbies in the ass. I've seen quite a few unintentional wheelies as a new rider botches an upshift and gets the timing between the clutch and throttle wrong and end up throttling too soon and drop the clutch and loop the bike. I've also seen guys do the exact opposite and botch a downshift and lock the rear, freak out, and lay the bike down. Many of these new riders in their group don't actually really down shift when coming to a stop. They've trained themselves to downshift once they come to a stop. Also, many new riders on super sports don't really know how to properly modulate the brakes and often use way too much initial force and tend to stab the brakes. They don't realize that you can use just a finger or two at most to get all of the braking force you will need to stop. I've seen these same noobs on super sports go over the handlebars from getting on the brakes too hard too fast and they don't have the newer bikes that come with ABS. I remember talking to some of the more "senior" noobs and they'd tell other riders to use mostly the rear brake so you don't launch yourself over the bars. Thought I was talking to a group of crusty old cruiser riders. This pack of sport bike riders that my friend used to hang out with never took a class and I believe they probably don't have licenses either.
I've watched these putzes make every noob mistake you can on a super sport and I know that the same mistakes on a ninja 300 or 250 would take a lot more work of ignorance to achieve the same results you get on the super sports. I've watched my friend go through wrecked super sport after wrecked super sport during his learning process and he was the better one of the group because he at least did the MSF course and got his license. I've noted something interesting though in that noob riders have a tendency to develop and employ work arounds to control issues rather than achieve mastery over the control in question. To avoid locking up the rear when downshifting, they try to keep away from downshifting until they've stopped or come to a near complete stop. To prevent going over the bars from grabbing too much brake, they barely use it and rely more on the rear brake. Throttle issues, well they want to go fast so this is an accepted risk for them.
While not impossible to learn on a super sport, it's a lot more work and can really slow the learning process down and potentially may encourage a new rider to employ work arounds for the harder things and develop some pretty bad habits. This effect seems to get a lot worse when these noob riders congregate in semi-permanent groups and those with bad habits and techniques pass them on to the newer riders who don't know any damn better. I like to call these "squid farms." My local community college has a "squid farm" "chapter" and it's pretty funny to watch them ride. There are a couple of really good riders mixed in their group, but I assume these guys don't really do much if any instruction or advice.