Exactly. If there's a learning curve (experience or time needed to make it start working), then that means the process undoubtedly contains subjective elements.
Developing solid aiming skills is similar to learning how to juggle. The exact steps can be defined objectively, but performing the steps correctly and accurately enough to make it all work is a matter of subjective feel (visual experience and muscle memory).
Hell, telling someone how to throw a baseball is objective. But developing the skill needed to accurately throw the ball at a precise target requires subjectivity.
Aiming pool shots is similar, because there are objective and subjective elements involved. Bottom line is... no matter what aiming method you use, the more you do it the more you learn all the little subjective parts needed to make it all work, and that's when it begins to seem "objective".
