I completely see your point, and in many cases I agree with you. But there is sometimes a tendency for evolutionary biologists to assign deeper reasons to thing

I completely see your point, and in many cases I agree with you. But there is sometimes a tendency for evolutionary biologists to assign deeper reasons to things that are just a consequence of physics. Occam's razor and all that. In this particular case that fact that the phenomenon is not present when the nerves are severed does present a pretty relevant argument against simple biomechanics.