That comment requires context, and the headline is flamebait. What Zuckerberg meant is that you can't treat the iPad like you do a mobile device such as an iPhone or Android-based phone. He's 100% correct too. The best iPad applications share only one key aspect with iPhone applications: the touch UI.
Indeed, but it was not actually what he said but the way he said it. He abruptly cut the question off as if he was talking to a friend and not the media. This is why Tseng cut in and explained the situation with calmness and professionalism. Had the question been directed at Tseng it would not make headlines.