However, its still worth distinguishing this sharply from deontology, because if you ever did calculate and find a situation in which your rule resulted in lesser utility – like pushing the fat man in front of the train – you’d break the rule.

But the moment you allow sub-rules as exceptions to the general rules like in the quoted part above, you set the ground for Rule-consequentialism to collapse into Act-consequentialism via an unending chain of sub-rules. See Lyons, 1965.

Further, as a consequentialist, you have to think about the effects of accepting a decision-theory which lets you push the fat man onto the train tracks and what that means for the decision processes of other agents as well.