pakeha
How is it he wouldn't have known about Christians if they were a threat to public order and merited the death penalty?
"...but I could discover nothing more than depraved and excessive superstition."
Apparently they did hold their meetings in secret. Whether this was because they wanted to operate as a mystery religion, or because they reacted stupidly to being persecuted because they were cultish and secretive, I don't know.
Pliny does seem to know
of them, and has known
of them for a while. What he didn't know is what goes on at their meetings. Appaarently, he'd heard that they're cannibals (his remark about innocent food) and that they swear strange oaths (which also turn out to be innocuous). He may also be bewildered why they sing hymns to one man as if to a god, but won't spalsh some wine or burn some incense to another man as if to a god, Pliny's boss.
Regular secret meetings with no shared family or class relationship are what attracted law enforcement interest. Romans were suspicious about that sort of theng (and also about magic, it appears, especially if being used for political purposes). Meriting the death penalty apparently didn't take much beyond law enforcement interest. I think Pliny explains himself fairly well,
... those who persisted I ordered executed. For I had no doubt that, whatever the nature of their creed, stubbornness and inflexible obstinacy surely deserve to be punished.
Pliny doesn't care why they disobey him (the nature of the creed), but only that they disobey him, after being caught and fairly warned. (Oddly, this reminds me of Swedenborg's ideas about personal judgment after death: OK, you lived a faithless life, but here you are, you can see for yourself that Jesus really is running things, so do you now cooperate with Jesus or not?)
Marcus Aurelius didn't think much of the "Christian attitude," either. From
Meditations, Book 11, ~ 167 CE:
What a soul that is which is ready, if at any moment it must be separated from the body, and ready either to be extinguished or dispersed or continue to exist; but so that this readiness comes from a man's own judgement, not from mere obstinacy, as with the Christians, but considerately and with dignity and in a way to persuade another, without tragic show.
Which, oddly, reminds me of Jesus himself (supposedly) complaining about the insincere piety of the Pharisees, etc.
Pliny was also a member of Trajan's judicial council during three years. How could he not have known what to do with confessed Christians?
Is it possible that you've never worked in a bureaucracy? This a CYA memo, with a hint of buttering the bosses' cupcakes. He's
already done something with the confessed Christians, he just wants to make the sure the boss is on board with that.