Imagine you have two groups of people: Group A and Group B. You are voting on a technology that can prevent 90% of deaths in Group A. Do you vote yes or no?
If you vote no, congratulations, you just condemned a large group of people to continue dying for the sake of egalitarianism.
(The reason this thought experiment is powerful is that it strips the scenario of value-judgments such as "elite" and "poor.")