Sam Harris uses the word “balkanization” in episode #204 of the Making Sense podcast with Jonathan Haidt. Sam uses the word as a noun at 51:57 of uses the word in reference to how social media has led to a “balkanization of our epistemology“, particularly among the younger generations who have never lived without exposure to it.
The verb form of Balkanization is “Balkanize”.
The word Balkanization is rooted in the Balkan Peninsula, which was under single control by the Ottoman Empire until it was broken up into a number of smaller states in the early 20th century.