Why do we need organized religion?
Dennis Prager & Joseph Telushkin, The Nine Questions People Ask About Judaism, p. 41:
We need organized religion for the same reason we need organized political parties, or any organized social movement. Whether it be to attain national independence, elect a particular candidate, or, in the case of Judaism, perfect the world through ethical monotheism, people with similar values and goals must organize themselves in order to have an effect upon the world.