I do see those few lines in TLB as being pretty harsh, though I also assume that they come from different sources. I think Eustace, Polly, and Jill don't understand what is going on. I personally find Peter's words very harsh though, harsher than membership or not in their club. Though, as Animus mentioned above, I do like the idea that it could be nothing more than her refusal to join in their scheme to get the rings.

As for the killed/accident, it's a good point. You could easily have Susan come to the conclusion, for instance, that it is evidence of evil and stuff happens in the world -- bad things happen to good people certainly is one way to approach it as a theological/philosophical question.