Cars have a lot more things on which they can vary - headlights, interns, bumpers.
And there's things that vary on these tablets, too. The volume controls, headphone jack (location, whether it exists, which size jack, etc.), MicroSD slot or not, HDMI or not...
A different engine. It's really difficult to make a 1:1 copy of a car. OR even a 60% copy.
But this case isn't about the internals (which vary widely between Apple tablets and non-apple tablets anyways).
EDIT: Screw it, you Apple nay-sayers will just continue this for AGES. I'll let you guys think what you want while I'll enjoy my Android tablet
Apple's logic is stupid, even the courts recognize it and are punishing Apple for such a frivolous suit (which is the point of this thread).