The cueball doesn't know how the hit was delivered. Inanimate objects have no knowledge or memory.
What does matter is that humans are meat balloons supported by flexible sticks held together with rubber bands. So when someone says that a stroke has to be performed a certain way, what they are really saying is that they have to perform it that way because of how their body reacts to the forces of the stroke. In other words, you can't put force (i.e. cuestick acceleration) into one part of a flexible system (i.e. the pool player) without that flexible system moving to resolve that force. Therefore, a person needs to compensate somehow to get the reaction needed.
To bring this further, humans are all relatively similar, so what works for one person will likely work to some degree for another. The outliers will have less success learning from the masses (for example, I'm 6'3" 165lbs, what works for someone a foot shorter and 20lbs heavier than me won't work as well for me).
So, there is kind of an absolute truth in what a lot of players claim, but the understanding of why is questionable at best.
