I too see the dust specks as obvious, but for the simpler reason that I reject utilitarian sorts of comparisons like that. Torture is wicked, period.

I think you have misunderstood the point of the thought experiment. Eliezer could have imagined that the intense and prolonged suffering experienced by the victim was not intentionally caused, but was instead the result of natural causes. The "torture is wicked" reply cannot be used to resist the decision to bring about this scenario. (There may, of course, be other reasons for objecting to that decision.)