Funny, I thought the exact opposite; I agreed on the general point, but found the arguments against iPad bit weak. First of all they were factually incorrect. As others have demonstrated there are plenty of apps that allow programming the iPad in a way that is at least comparable to TIBASIC. You don't need developer accounts or review processes to use those apps.
More importantly the author missed the part that iPad is essentially just a platform, a tabula rasa if I may say so. As it does not provide any educational features on its own (afaik) some apps need to be provided by the school. And those apps provide the discoverability aspect that is missing from a vanilla iPad. It is reasonable to think that school would provide/require an app (or a collection of apps) that would be an equal or surpass the features of a graphing calc, including the programming features.
Of course I'm not really sure what educational apps are currently available, if they are adequate. But if not, then that would actually be something that HNers could do something about.