I suggest that this is true because the others ARE YOU.
ARE YOU in the sense that we are all God. Are God in the sense that we are from God / of God, and everything that emanates from God is God.
And that we are also simultaneously not God, and similarly not the others, does not change the fact that we are the same at the same time.
I propose that our believing we are not God and not each other facilitates something we are after. But in the course of going about our business, might it not make for a better world to occasionally reflect upon our oneness?