My algorithm goes like this:
there are two variables, X and Y.
Adding a single additional dust speck to a person's eye over their entire lifetime increases X by 1 for every person this happens to.
A person being tortured for a few minutes increases Y by 1.

I would object to most situations where Y is greater than 1. But I have no preferences at all with regard to X.

See? Dust specks and torture are not the same. I do not lump them together as "disutility". To do so seems to me a preposterous oversimplification. In any case, it has to be argued that they are the same. If you assume they're the same, then you're just assuming the torture answer when you state the question - it's not a problem of ethical philosophy but a problem of addition.