I don't understand why this is a rationality quote. Am I missing some context? (I've never read any Charlie Brown books).
I believe this is from a tv special; I'm having trouble determining the relevance as well.
One possibility: the extended description of the story, rather than a simple statement of fact or belief, constitutes a warning about the power of contextual imagery in activating availability heuristics.
A monthly thread for posting rationality-related quotes you've seen recently (or had stored in your quotesfile for ages).