I take it you have ridden a modern engine that revs to 13500 RPM! GM & Jawa build, develop engines for the modern tracks, ie Sweden Poland big smooth wide open bends. under NORMAL conditions the engines work fine. These are not 2 valve Jawa's or even 1975 Weslakes!!!
To be fair, these modern engines that rev to the heavens and if a track is unpredictable it could be very dangerous. lets be honest, riders safety comes first