Why? I've only used an iPad a couple of times and I didn't find it very easy to type on, especially if you need numbers, brackets, a dash etc. Maybe it's something you have to get used to. Or maybe you have to get one of the keyboard docks (http://store.apple.com/us/product/MC533LL/A), but that's not very portable.
Don't get me wrong though, I totally agree that it was a cheap shot at the iPad. Although I can't imagine using the iPad to get things done, it seems pretty good for consuming content though.