Business is business
religion is primarily a business.
so it always was, so it always will be.
religion sells warm-fuzzies, righteousness, guilt, power, and the excuse to brutalize and/or kill those who do not believe EXACTLY as you do (according to the methodology of your particular church, or other faith-based murder-license-granting institution). there are some other accessories (processions, holidays, outfits, facilities, hatreds, etc.), that vary by cult.
in the US, religion is a trillion-dollar, tax-free business.
if a church is also a state (see GW Bush & Gang), all the better, as it makes for a bigger (also more righteous and more deadly) business. a church that is a state has the special ability to mount Crusades (this is armed robbery writ large, see below for references).
for more historical examples (a non-exhaustive list), see:
-the Holy Inquisition
-the Salem Witch Trials
-the Divine Right of Kings
-abortion clinic bombers
-Red Army Faction (ideology as religion)
-Baader-Meinhof Gang (same as previous)
-the Cultural Revolution (and again)
-Ancient Rome ("Jews vs. Lions")
-"The 300" (Xerxes was a God-Emperor)
-Ancient Egypt (the Pharaohs were considered semi-divine)
-Sunni vs. Shi'a (vs. New Crusaders)
or any other 2-to-5-way matches by Christians vs. Muslims vs. Jews vs. heathens vs. "unbelievers" throughout recorded human existence.