I was about to make another slam at Cicero to accuse him of "emending" it out, but there's no reason not to think that a conclusion based on this was in the version that Cicero had available to him, and that it wasn't cut out by some "helpful" church fathers long after Cicero's death.
In fact that's probably more likely, because Cicero likely couldn't trust that he had the only copy of the poem and that his version would become the official one.
So it's entirely possible that something like this was there and just added to Cicero's frustration.
And if so then that would leave the book, if not the whole poem, ending on much the same note that Frances Wright chose for "A Few Days In Athens"