There is still no evidence that they did that, or that it altered Christians’ own beliefs accordingly. Pliny never even says Jesus was a historical person. And the first time pagans mention it, they are responding to the Gospels, which are Christian documents. (Refs. in Josephus and Tacitus being evident Christian forgeries.)

So, we can’t get anywhere with this. Speculation in, speculation out.

Meanwhile, Porphyry is arguing a fortiori. He has and claims no special knowledge of what happened in the first century.

I agree. But I would like to consider a prima facie similarity between your modern anti-apologetical arguments and Porphyry’s case against Christianity (as expressed in his survived fragments). In short, I see the same logic at work:

1) if read literally (=that Jesus is really a man), then the Gospel episodes sound false.
2) It is a pure and simple fact that Jesus is a mere man.
3) Therefore the Gospels are probably false.

It is curious that Eusebius (the real author of the Testimonium Flavianum in reaction to Porphyry’s polemical attacks, according to Ken Olson’s “A Eusebian Reading of the Testimonium Flavianum”) accepted basically the correct logic of Porphyry, but he denies paradoxically his conclusion, by making a clear logical error :

1) if read literally (=that the Son of God is really a man), then the Gospel episodes sound false.
2) It is a pure and simple fact that the Jesus is a man.
3) Even so, the Gospels are true.

Remember the incipit of the Testimonium, showing doubt about the presumed humanity of Jesus:

About this time there lived Jesus, a wise man, if indeed one ought to call him a man.

Why was the Pagan Porphyry apparently more historicist than the Christian historicist Eusebius?

Is not there the concrete possibility that the people didn’t call Christ ”a man”, but only ”a deus” ?

I think that the ancient anti-Christian polemists, just as you are when you have argued against banal Christian apologists about resurrection et similia, had need of assuming a historical Jesus in order to make their arguments. In other terms, this would prove that the Pagans had clear interest, also them, to euhemerize the mythical Christ, to deny that Jesus is a DEUS (because the only way to ransom the truth of the Gospels is to read them allegorically as allegories of a mythical hidden truth, not true history, something that Porphyry was reluctant to do, because otherwise he would have legitimated the Christ’s cult). Evidently the people called Christ a ”deus” (see Pliny) and not a man, contrary to Eusebius. And if Pliny was skeptical about the real deity of Jesus (as some people want to interpret Pliny’s words ”quasi deo”), was so because already Pliny was going to euhemerize Jesus independently from what he listened about Christ by Christians themselves?

Curious to know your opinion about.