I like this post, but I think that it suffers from two things that make it badly written:

• Many times (starting with the title) the phrasing chosen suggests that you are attacking the basic decision-theoretic principle that one should the take the action with the highest expected utility (or give to the charity with the highest expected marginal value resulting from the donation). But you're not attacking this; you're attacking a way to incorrectly calculate expected utility by using only information that can be easily quantified and leaving out information that's harder to quantify. This is certainly a correct point, and a good one to make, but it's not the point that the title suggests, and many commenters have already been confused by this.

• Pascal's mugging should be left out entirely. For one thing, it's a deliberately counterintuitive situation, so your point that we should trust our intuitions (as manifestations of our unquantifiable prior) doesn't obviously apply here. Furthermore, it's clear that the outcome of not giving the mugger money is not normally (or log-normally) distributed, with a decent chance of producing any value between 0 and 2X. In fact, it's a bimodal distribution with almost everything weighted at 0 and the rest weighted at X, with (even relative to the small amount at X) nothing at 2X or 1/2 X. This is also very unlike the outcome of donating to a charity, which I can believe is approximately log-normal. So all of the references to Pascal's mugging just confuse the main point.

Nevertheless, the main point is a good one, and I have voted this post up for it.