The only similarity between those cases is that they involve utility calculations you disagree with. Otherwise every single detail is completely different. (e. g. the sort of utility considered, two negative utilities being traded against each other vs. trading utility elsewhere (positive and negative) for positive utility, which side of the trade the single person with the large individual utility difference is on, the presence of perverse incentives, etc, etc).

If anything it would be more logical to equate Felix with the tortured person and treat this as a reductio ad absurdum of your position on the dust speck problem. (But that would be wrong too, since the numbers aren't actually the problem with Felix, the fact that there's an incentive to manipulate your own utility function that way is (among other things).)