I guess I will give everyone a little tuning primmer.
First, you must understand that there are two types of deformation, elastic and plastic.
Elastic deformation is the stage that any material goes through where, when deformed, it will return to its original shape every single time. Once there is enough deformation to go past this stage, the material is said to have enter plastic deformation.
Plastic deformation is actually where the material is being deformed and will not return to shape.
Take for example a rubber band. If you expand a rubber band a little it will always return to shape, and you can literally do this indefinitely (and it will not matter what speed you do it at). Now if you take the same rubber band and expand it out wide it will permanently stretch out of shape.
The same thing applies to plastic used in discs. For discs, the better the plastic the greater the elastic range and the greater the limit of plastic deformation. In other words, it takes a much greater deflection to permanently deform better plastics. Cheaper plastics permanently deform at much less defection. This explains why premium plastic discs do not “beat in” from collisions like cheaper plastics (this also explains why some plastics simply SUCK for discs because they permanently deform within the force collision range of normal tree hits).
So, to answer your question, the speed of the deflection is not the key, it is the AMOUNT of the defection (think of the rubber band example). Star discs and ESP discs take bending the rim nearly double back on itself to deform the disc.
You can learn more about defection here:
"The reasonable man adapts himself to his environment. The unreasonable man adapts his environment to himself, therefore all progress is made by unreasonable men."
-George Bernard Shaw