So, let's see if I got this right (someone please check my work):
Some people claim that only intentions determine moral guilt/innocence. This is incorrect because external factors (the consequence of one's actions), regardless of ones intentions, often play a crucial role in our moral judgment of an action. A chef is thus blameworthy if he, unintentionally, happens to put in an ingredient that is not included in the original recipe of a stew if someone eating the stew is allergic to that ingredient.
D: This answer choice encapsulates the argument presented in the question stem. Contrary to what some people claim, people can sometimes be held morally blameworthy for the consequences of their actions regardless of their intentions.
A: The columnist does not make a normative statement about when it is fair (i.e. legitimate) to judge the morality of others. He merely states an observation that contradicts a claim made earlier by others. Also, the argument put forward by the columnist is about whether intentions is the sole determining factor for considering an action blameworthy or not and hence this answer choice is out of scope.
B:Same problem as A. The author never makes a normative statement.
C: Same as A and B.
E: The problem with this answer is the word "rarely": it's not supported in the stimulus. The author does not say that intentions do not matter, only that intentions are not the only thing that matter. Consequences matter too.