sotto voce

Then what was his purpose, mocking YECism every time he stood up?

Very good. Bob Hope thought he was a comedian.

Certainly not— ask a Protestant! Of course, murderous Catholics are not novelty. Catholicism is premised on murder, or its threat, as you are aware, and as is logically necessary, anyway. But baptising, then immediately murderous Catholics are novelty. So why would the scion of a family that had remained close to power and wealth since they passed from the grasp of Catholics invent such a tale, as, it would appear, this one did?

The idea of Romanism is to hold the believer in a state of dependency on priests, so that the greed of the people who exploit the labour of the believer, who also effectively employ the priests, is fed. So there does not seem to be any point in killing off those who are to keep one in creature comforts. But a story that tended to suggest that priests and their affluent associates were uninterested in pelf would appeal to them, as good propaganda. So a story of this type could have suited Russell's purpose. In the absence of any alternative explanation, this seems to me to be the only reasonable one.