Two hypotheses about the reason of this drastic judgement of Papias by Eusebius:
- The contempt was the result of a respected, imperial position in a now triumphalistic, resplendent and glittering Church (325 C.E.)
- Eusebius was embarrassed that Papias had led a secret out: the very humble origins and repetitions of learned and folk wisdom contained in the Logia. The information that Matthew translated the Logia from Aramaic is not a particularly impressive endorsement of The Gospel According to Matthew.
Hence, Richard Carrier is correct: Papias's stupidity in the eyes of Eusebius is more expected under mythicism than under historicity.