organized religion can get pretty retarded, especially when you throw traditionalism and closed mindedness in the mix. but it works for people, some who are transcendent and social find that worshipping god with others helps themselves feel better. it also helps develop moralities for those "good vs evil" people who arent intelligent enough to develop their own sense of morality.
however, youll often find that those devout religious followers often have rather 'sinful' immoral motivations. those who believe theyre always right for instance, like you mentioned, arrogant people. theyll get into religion and possibly clerical duty in order to feed their own insecurities and gain a sense of "im right gods on my side your evil, sinful, and possibly going to hell"