Your point about the fractal structure of tribalism reminded me of this joke:

I was walking across a bridge one day, and I saw a man standing on the edge, about to jump. I ran over and said: "Stop. Don't do it."

"Why shouldn't I?" he asked.

"Well, there's so much to live for!"

"Like what?"

"Are you religious?"

He said: "Yes."

I said: "Me too. Are you Christian or Buddhist?"

"Christian."

"Me too. Are you Catholic or Protestant?"

"Protestant."

"Me too. Are you Episcopalian or Baptist?"

"Baptist."

"Wow. Me too. Are you Baptist Church of God or Baptist Church of the Lord?"

"Baptist Church of God."

"Me too. Are you original Baptist Church of God, or are you Reformed Baptist Church of God?"

"Reformed Baptist Church of God."

"Me too. Are you Reformed Baptist Church of God, Reformation of 1879, or Reformed Baptist Church of God, Reformation of 1915?"

He said: "Reformed Baptist Church of God, Reformation of 1915."

I said: "Die, heretic scum," and pushed him off.