“I recommend observing real life and learning history. People have rarely been treated as inherently equal and yet it very often happened that “one person’s agency or vision” was respected. Do note that people’s capabilities vary greatly and reality doesn’t care at all about equality or fairness.”
That essentially relies on chance. A person’s agency is most likely to be respected by me if, by chance, I see that person as roughly my equal. Most people don’t worry about violating the agency of a dog nearly as much as they worry about violating the agency of another human (although this obviously depends on one’s definition of personhood). The agency of African American people in the U.S. was frequently violated because they were perceived as being different from, and lesser than, white people.
Proximity plays a noted role, here. There’s generally a greater concern for the agency of those near you than those you don’t know about, because the only violations of agency you care about are those that seem to be a threat to you. I just think that personhood is a valuable enough thing that we ought to be more systemic in how we protect the agency of things which fit whatever definition of personhood we agree to.
“Yes, this is correct, but I don’t see how is this related to the willingness to sacrifice others.”
You cannot say that there is a right for you to sacrifice other people against their will, because, definitionally, you cannot willingly abide by the obligation to sacrifice yourself against your will for other people.
As I said in response to Lumifer’s post, the problem is this still leaves it up to chance. We may come to the same conclusions on one thing or another, but that is purely by accident, and if we should begin to come up with different moral axioms, I have no reason to respect his viewpoint if a.) I have no guarantee that he’ll respect mine, or b.) I have no axiom which states that I should respect other moral frameworks even if they’re different from mine. Certainly, there are many instances in which both parties to a discussion discover an idea they agree upon, but the debate continues because of how the agreement was come upon, when it shouldn’t matter.