People often use thought-experiments to try to criticise utilitarianism as an ethical system, but 've never read one that was convincing. I remain a rule-utilitarian.
I think rule utilitarianism works at a societal level in that having generalised rules then covers our social contract, but essentially on a day to day basis for how I act in a situation, it's a sort of modified and personally adjusted act utilitarianism, and I think that's what the article is suggesting. I'm aware of my imperfect knowledge, and also I am self interested in that my happiness is worth more to me.
I think that the society level can be 'For the many, not for the few'but that reverses on my own decisions. When there was theq long discussion on this board about objective morality, and Alan (Alien) was using the question of whether it could ever be right to torture a child to death just for fun, the case of whether if the person said if they asked to torture the child to death, or else they would break a vial that would release a deadly virus, andmist people said then they would allow it, I disagreed. If I could save the child I would.