In the most simplistic of terms what the negative ego is seeking to do is divide and conquer. As the world splinters, it cannot maintain its power.
War is the epitome of alienation and powerlessness. Even the greatest armies are powerless against themselves in war.
In order to do injury to anyone (including yourself), you must be alienated from them.
You are all one because consciousness is one. That's the bond you share that you all have consciousness and that is the source of your oneness.