It was cross-posted on LessWrong when it was published last winter, but not on the Forum, so I'm making a Forum post for it now.
Here's an excerpt:
Carl: “Well, it’s still plausible that they are effective, so I can’t condemn—”
Worker: “Stop. In talking of plausibility rather than probability, you are uncritically participating in the act. You are taking symbols at face value, unless there is clear disproof of them. So you will act like you believe any claim that’s ‘plausible’, in other words one that can’t be disproven from within the act. You have never, at any point, checked whether either charity is doing anything in the actual, material world.”
Carl: “… I suppose so. What’s your point, anyway?”
Worker: “You’re shooting the messenger. All or nearly all of these charities are scams. Believe me, we’ve spent time visiting these other organizations, and they’re universally fraudulent, they just have less self-awareness about it. You’re only morally outraged at the ones that don’t hide it. So your moral outrage optimizes against your own information. By being morally outraged at us, you are asking to be lied to.”