As Maharaja has quoted me, I wrote, “But if Srila Prabhupada is fallible in his own books, how could anything else he says in them be trusted?” I did not make the claim that “all that Prabhupada says” is true. This distinction matters because on the one hand it acknowledges that a guru even of Srila Prabhupada’s stature is not omniscient and, for example, might be mistaken about how the latest iPhone works. And on the other hand, it asserts that there are some domains in which Srila Prabhupada’s opinion should be considered infallible.
For example, in his own statements in his own books, it is self-evident that he is self-consciously speaking as a representative of our parampara. If what Srila Prabhupada says in his own books does not always faithfully represent our parampara siddhantas, then apasiddhantas are sometimes to be found in his books. This is what Maharaja’s 2005 paper on moral theology implies about Srila Prabhupada’s purport to SB 3.20.26. If it is the case that in Srila Prabhupada’s own books there are some utterances of his that are apasiddhanta, then it follows that Srila Prabhupada has no standing as a spiritual authority.