Utilitarianism doesn't make sense. What Utilitarians should do is change their mind.
They want to promote the greatest good to the greatest number, or something like that. But how do you calculate how much good any given thing is in order to make decisions? Utilitarianism doesn't offer a viable way to calculate this, so utilitarianism doesn't actually give any clear indication about which actions to take or not take.
Instead the way utilitarianism works is people want to take some action (first) and then (second) make vague appeals to it being good for lots of people.
Also, people aren't all equal. The programmers who worked on the iPhone matter more than some guy serving burgers. They make a bigger difference in the world and help way more people. They are better at thinking and learning and problem solving. They're more logical and rational. They're on average more moral people who'd be easier to cooperate productively with. Take your pick of criteria and iPhone programmers will tend to beat burger servers.
(There are many breeds of Utilitarianism. If you pick one and ask a question providing some detailed claims about how it works, then I could comment on those specific claims. I think you'd want to submit this as a new question on the site. If I don't see it you can email me [email protected] with a link to it.)