This is an example of "procatalepsis" or "prolepsis" [1], a rhetorical device that is often used to try to defuse criticism. Authors often use this to try to slip something controversial by their readers [2].
It's interesting; I hadn't known the word 'prolepsis' but recently encountered it in another context, in which it was defined quite differently as "the representation or assumption of a future act or development as if presently existing or accomplished" (http://www.merriam-webster.com/dictionary/prolepsis). Is one of these references in error, or is the same word used to describe two very different rhetorical devices?