Good points.

It seems to me that people are also skeptical of those who claim to accomplish altruistic ends acting on self-serving motivations because of a common “rule of thumb”:

Benefits to charity are taken directly from the potential benefits of the donor.

Religion may be the main promoter of this belief. For example, the crucifixion of Jesus teaches the lesson that the greatest good came from the greatest sacrifice.

This assumption can only exist if charity payoffs from all (or a portion of) potential actions are unknown. If we can quantify these payoffs, perhaps we can eliminate the core uncertainty that spawned this rule of thumb, and, therefore, encourage optimal allocation of charity resources. That’s a big IF, I know.