I think these days, that many of the guys who ride modern superbikes, come up from motocross. A lot of them seem to believe you can but a foot on the road at high speed without twisting your leg and breaking it. There is much more to road racing than just riding the bike. I think Barry Sheene progressed by crashing Suzukis. The rider needs to shape what their mechanics do to the bike. I think that the young guy who crashed so badly in the NW200, then killed himself on the IOM, was a real tragedy. That should not happen. I raced regularly for several years when I was a kid and these days my bike helps me to be a fairly good rider. But with modern bikes, if it is wrong - it is extremely wrong.
In Australia, we've had a few ladies road racing on bikes which have been prepared for them. It is probably OK if the mechanic is very smart and questions them about what the bike is doing while they are riding. But with guys such as Peter Williams, they are much more hands-on and probably have a much better understanding of what needs to be done to make the bike better.
I don't believe in discrimination, but I have never known a lady road racer who could build her own motor and certainly not a complete bike. And many guys are no different.