As long as ethics are a part of morality, based on immaterial, personal truths, there will be no final answer for how we should treat one another that undeniably applies--both its protections and its obligations--to all human beings.

An ethic following from the observation within material existence--a material truth--that we humans have no choice but to effect choices provides such an answer.

If curious: "Justice Can't Just Be What You Want It to Be but it is what you probably think it is" (here in Medium, but not behind the paywall).