After all, they are brothers, and they are intertwined with each other even across the world.
When Itachi left for the first time, he was left with nightmares and deep hatred. Later, Itachi died, leaving him with a vague and sad love.
There is no liberation in life or death. I hold hate in my right hand and love in my left hand. Nothing else can be taken away.
But both of them are the most poisonous in the world.