Criticisms of utilitarianism often end up in a couple of camps, the first being extremely far fetched thought experiments, like the Utility Monster (which by the way, can be reversed on Nozick as a "property monster", which I came up with in this comic about: https://existentialcomics.com/comic/259). These push utilitarianism to its end, showing that it actually causes us harm. Kind of a poor criticism, since the whole point is to make us happy, the fact that it doesn't make us happy doesn't really work. Of course we all agree with the utility monster anyway, which is why we don't value the happiness of ants as equal to ourselves, we are the utility monsters. If some greater being came along, they would probably just laser us all to use earth as a beach house anyway, so we wouldn't have to worry too much about the failure of our philosophies to account for them.

More to the point though, people like Nozick, who spend their career arguing why it's great and fine for the rich to exploit the poor, obviously don't have humanity's best interest in mind. Most utilitarians spend their time on earth trying to make life better for everyone, like arguing for women's rights, animal rights, and alleviating poverty. So yeah, take your pick I guess.