Because cynics would realize you are exaggerating and perhaps think less of your product for it – maybe your product can’t stand on its own, so you have to exaggerate to make up for that. Apple is betting that most of its ad watchers are not this type of cynic.
Like that "what is iPad" commercial that says "all the world's websites". They made the best tablet going, so why do they still feel the need to cross the line between touting and lying?
All the websites are available of course. Whether or not you can make use of the Flash content is a different story. At least to Apple it's a different story...