Autocerebrolavatio

Coined from the fusion of "auto-" (self), "cerebro-" (brain), and "lavatio" (Latin for washing or cleansing). The term refers to the act of self-indoctrination or willful narrowing of one's own perspectives, often to the point of ignoring or dismissing evidence that contradicts one's beliefs.

"His constant exposure to only one news source has led to a severe case of autocerebrolavatio."
"She's so convinced of her own theories that she's fallen into a loop of autocerebrolavatio."