Reality has a way of turning out quite "inaccurate."
Your personal definitions of "PC", "tablet", etc., are irrelevant to the direction in which the market is headed.
Forward your objections to Canalys and DisplaySearch, and then in good time to IDC, Gartner, etc. And then, in time, take a stand against the entire industry, that has turned your definitions inside-out. But by that time you will have probably accepted it.
Notice something. Only some of the biggest Apple fans seem to agree with lumping the iPad in with a PC sells. The general consumers still consider them separate products.
The iPad is a great supplemental device but is still a long ways from a stand alone. The first product that I see in the future that is going to be able to truly bridge the gap is Windows 8 and even then it will be limited to only certain products that truly can jump between the two sides.
In terms of looking at tablet OS as a PC category iOS is the farthest from it and by far the worse of the desktop replacement OS's. Android Honeycomb and ICS are by far better replacements for standard PC OS. iOS well sucks in that department.