It may be proving too much, but it is also arguing the general point. Your objection would be that this example would prove that all strings are programs, which

It may be proving too much, but it is also arguing the general point. Your objection would be that this example would prove that all strings are programs, which might seem absurd. But in fact, all strings are programs if you haven't specify which interpreter they are supposed to be programs for. Either way, that seems like a silly approach, IMO.