Ffs, they know why. There were multiple smaller social groups. The old members keeping the peace died and the younger ones vying for dominance didn't get along.
The other article said there's a dude who's been watching them for 30 years. One would think he knows what happened and why. If only actual journalists still existed as a mainstream profession.
I'd say It's the same as when siblings fight for inheritance, they split off and hate each other till death.
