Argumentative ethics is not about determining "truth".

It's about deriving the minimal ethical that we can agree upon using a logic derivation.

If the aim is to determine possible agreement it requires arguments.

Coming up with arguments require private property, starting with self ownership, and extending it to objects that can be delimited, modified, and protected.

Turns out the requirement for private property is the minimal ethical, as we can only agree (or disagree) that we can form arguments.