Its basic engineering to be honest.
A force applied a distance away from a pivot point will create a lever. Which creats what we call a bending moment. The further you are away from the hub the larger the bending moment acka if it gets to big its instant damage and even if its not enough it adds to the fatigue history of the prop.
And a little weedy girl is more than capable of bending anything she likes with the correct application of force.