Seems rather obvious to me. iOS devices are post PC. So it would be like ask why doesn't Nike include sales of Cole Haan shoes in its athletic shoe sales report. Similar product, different category.
61% actually
I really thought it would be higher than 61%. What else has sold in any real numbers?
Because this report is a market analysis and not a semantics argument. iPads and similar devices compete within the PC market for customers. Research has shown that they have had an explicit impact on netbook sales. It's not a question of whether it meets your preferred definition of the term "PC".
But since it meets yours it's ok, right?