In the Utah/Nevada/Idaho/Wyoming area where the story is situated, zealotism has led to suffering and lives lost. The Mormons were known to subject homosexuals to electro-shock therapy, and vigilantism was practiced by religious groups and other extremist groups. It was in such an atmosphere that the horrific death of Earl was allowed to happen and was witnessed by the 9-yr-old Ennis.
def: \Zeal"ot*ism\, n. The character or conduct of a zealot; zealotry.