Public-choice theory rules out interpretive charity in advance. All that is left is the imputation of bad motives to one’s political opponents.
. . .Actions may be objectively evil, but subjectively, everyone is doing what they think is somehow justified. Attributions of (subjectively) evil motives end the process of scholarship before it can begin. In studying politics, we want to know (among other things) why evil results may flow even from good motives—as an unintended consequence.
Read the whole post. There is a strong temptation to believe in asymmetric insight, meaning that you claim to know the other person’s motives better than they know themselves. This is a temptation that one ought to try to resist.
Friedman is somewhat hard on public choice theory. I have been hard on it myself. Still, it has some value, as when it predicts that public policies in areas like housing or health care will tend toward subsidizing demand and restricting supply.