Absolutely agreed. But it's about conflicts among preferred outcomes of a decision, not about preferences among disconnected world-states.
Less about two outcomes your preferences conflict on, and more about, say, your preferences and mine.
Insofar as your internal preferences conflict, I'm not certain ethics are the correct approach to resolve the issue.
If they're unaware because there's no reasonable way for them to be aware, it's hard for me to hold them to blame for not acting on that. Ought implies can. If they're unaware because they've made choices to avoid the truth, then they're ethically inferior to the version of themselves which do learn and act.
This leads to a curious metaethics problem; I can construct a society of more ethically perfect people just by construction it so that other people's suffering is an unknown unknown. Granted, that probably makes me something of an ethical monster, but given that I'm making ethically superior people, is it worth the ethical cost to me?
Once you start treating ethics like utility - that is, a comparable, in some sense ordinal, value - you produce meta-ethical issues identical to the ethical issues with utilitarianism.
more ethically perfect people
You're still treating ethical values as external summable properties. You just can't compare the ethical value of people in radically different situations. You can compare the ethical value of two possible decisions of a single situation.
If there's no suffering, that doesn't make people more or less ethical than if there is suffering - that comparison is meaningless. If an entity chooses to avoid knowledge of suffering, that choice is morally objectionable compared to the same entity seeking knowledge of such.
You can...
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