Hi all,
hope can find some answers to my questions here. I will try to abbreviate.

If there is objective morality, then equal interests per life time for each sentient being should be the aim to achieve. Therefore:

1. Utilitarianism can not be objective because it ignores the distribution of well-being and separateness of persons.

2. Theories considering the separateness of persons on the other hand, can have one of the following results:

2.1 Libertarianism:
This can not be objective because it ignores the distribution of well-being.
2.2 Egalitarianism
Even if we assume that some version of it aims at providing equal interests per life time for each sentient being, it can not achieve that.
People are not going to end up having equal well-being. You can not prevent that some individuals will end up worse off than others. You can not control how each individual lives and dies.

If you think this is not an argument against separateness of persons, think about this:

If separateness of persons is true in the egalitarian sense, then the world is equally bad or good whether one person/sentient being or all persons but one person in the world is worse off.

If separatness of persons and egalitarianism are requirements for objective morality, then as long as there is one human or sentient animal suffering or going to suffer, it makes no moral difference to help others.
The problem is that it does seem these two are requirements of objective morality.

As long as illness and natural disasters happen to humans, carnivorous animals have to eat other animals or suffer and die themselves, we can not provide equal wellbeing to each sentient being. And if we can not that, then separateness of persons and equal distribution of well-being will be both required for objective morality to exist and impossible to achieve, which only leaves us with the option that it is imaginary!

Is objective morality based on trying to make a perfect world that can only exist in imagination?