While the author presents the graphics tablet as a glorified mouse, tablets usually offer many more features. How those features interact with various applications is important, and they have to prioritize which applications they support. The data collection that the author describes may be viewed, internally, as part of that process.
Now I am not claiming that Wacom is doing the right thing, nor am I claiming that they are doing the right thing in the wrong way. Yet it is entirely possible that they feel justified in collecting that data for product development without having ulterior motives. Their failure may simply lay in the failure to recognize that many people are sensitive to data collection due to real, potential, or perceived abuses by other parties.