Carrier is a shill, a stool pigeon for Christian hegemony, only pretending to oppose orthodoxy.
You aren't willing to allow for the possibility that he's just mistaken? "Shill" is a pretty strong pejorative, implying that he's on someone's payroll. I don't see any evidence of that.
Unlike some of the climate denier "shills" who are clearly taking funding from Koch brothers or fossil fuel industries. I'm not above calling people "shills", but only when the evidence is undeniable.
In fact, I'm willing to allow some slight chance that he's right and we're wrong.
For example, regarding the Triptych: I agree that there's a logical relationship between the three sections. That is: first the mention of Jesus Christ and his resurrection on the third day; next, the tale of Decius Mundus, his deceitful courtship of Paulina, and his revelation on the third day that he is not God; and finally, the story of a wicked man and his henchmen who trick Fulvia into giving up her wealth to her, leading to banishment of the Jews from Rome.
Now, it's completely possible (as many scholars
including Carrier argue) that the Testimonium Flavianum, the first part of the Triptych, was not written by Josephus. Perhaps the text originally included some very different story about Jesus and his resurrection.
But, how credible is it to argue that the character of Decius Mundus is not a satire of Jesus? And, how credible is it that the wicked man in the Fulvia story is not Paul? It seems to me that the parallels are very dense and highly interpretable. And it follows that if the currently existing Testimonium Flavianum is a fake, it must have replaced an earlier, highly incriminating satire of Christian beliefs about Jesus and the Resurrection.
But, I also feel this way about the Cannibal Mary story. Carrier is fully aware of Cannibal Mary, and he thinks that this story is just a riff on Numbers 12 and on the Jewish concept of Passover. He thinks that Atwill's parallel is refuted because some details don't match:
https://www.richardcarrier.info/archives/4664
What Josephus seems to have in mind is to communicate that Jewish society had been turned upside down by rebellion, and he does this by turning the Passover upside down. Hence we have here a Jew’s own poetic inversion of the Passover to make a contextual point about the state of society during the siege of Jerusalem. This does not suggest or require any knowledge of or allusion to Jesus or Christianity.
Had the baby been called Jesus, then Atwill might have had something. Or if the Gospels identified the mother of Jesus as “Mary the daughter of Eleazar” or “from the town of Bethezob,” as the Mary in Josephus is. Or had any Gospel identified any other Mary as being the actual daughter of Lazarus (“Eleazar”), instead of his sister, as only one Gospel actually does (Jn. 11:2). But alas, no such connections are there. Otherwise, Mary is too common a name to be remarkable, as is Eleazar. And the Gospels fail to identify Lazarus as from Bethezob but instead from Bethany. So it’s the wrong Lazarus. And Mary is his sister in John, not his daughter as in Josephus. And even this Mary (in John, the only Mary connected to a Lazarus at all, and by the wrong family relation) is not the mother of Jesus. So it’s also the wrong Mary.
So on every count a parallel is refuted here, not established.
Now, Joseph Atwill's full list of parallels for Cannibal Mary is:
...within this short passage Josephus has used a number of concepts and names that are parallel to those associated with the New Testament’s symbolic Passover lamb. These are a mother named Mary; the fact that this Mary was pierced through the heart; a son of Mary; hyssop; a son who is a sacrifice; a son whose flesh is eaten; a son who is to become a “byword to the world”; one of Moses’ instructions regarding the Passover lamb; an individual named Lazarus (Eleazar); and Jerusalem as the location of the incident. (Caesar's Messiah, Flavian Signature Edition (p. 60), Kindle Edition.)
It seems to me that Carrier's demand for a perfect match of every element of a typological parallel or pesher, before the parallel can be accepted, is completely unprecedented. I don't believe there's a single example of such an accepted parallel where there isn't some variation between the later version and its source. Otherwise how could an old passage be reinterpreted in a new light, and what would be the point of writing the new version anyhow?
Let's look at Carrier's proposed parallel from Numbers 12. He states it this way:
A rebellious Mary from the days of the Passover, associated with a half-consumed baby.
And that's it.
The Numbers passage is about a baby consumed by disease, not cannibalism. And it's a metaphorical baby, not even an actual character in the story. Mary repents of her rebellion, and is forgiven. This is supposed to be the stronger parallel?
Or, in the broader context that Carrier thinks that Josephus is inverting the Jewish concept of 'Passover': the details of the parallel that aren't included are the "pierced heart"; the "son of Mary" (notwithstanding that she's the 'wrong Mary', still her name is Mary); the "byword to the world"; and the name Lazarus (Eleazar).
Nevertheless, could Carrier be right that Josephus was thinking about Numbers 12 and the Passover, and not the Gospels? Could this level of parallelism happen unintentionally, or beyond Josephus's conscious awareness?
Seems to me that Atwill is right, and Carrier is wrong. But, a mathematically solid proof eludes me.