I don't think most utilitarians claim to follow (or even know) their utility function so much as assert that utility maximization is the proper way to resolve moral conflicts.
Kind of how like physicists claim that there would be a theory of everything without actually knowing what it is.
I perfectly agree that utility maximisation is indeed the proper way to resolve common moral conflicts.
But utility functions can be as complex as you need them to be! Saying you have a utility function does not constrain you virtually at all. But sometimes total utilitarians like to claim that their version is better because it is "simpler" or "more intuitive".
First of all, simplicity is not a virtue comparable with, say, human lives or happines, secondly I have different intuitions to them, and thirdly, their actual real utility functi...
Some people see never-existed people as moral agents, and claim that we can talk about their preferences. Generally this means their personal preference in existing versus non-existing. Formulations such "it is better for someone to have existed than not" reflect this way of thinking.
But if the preferences of never-existed are relevant, then their non-personal perferences are also relevant. Do they perfer a blue world or a pink one? Would they want us to change our political systems? Would they want us to not bring into existence some never-existent people they don't like?
It seems that those who are advocating bringing never-existent people into being in order to satisfy those people's preferences should be focusing their attention on their non-personal preferences instead. After all, we can only bring into being so many trillions of trillions of trillions; but there is no theoretical limit to the number of never-existent people whose non-personal preferences we can satisfy. Just get some reasonable measure across the preferences of never-existent people, and see if there's anything that sticks out from the mass.