Negation also explains why religious people tend to hate and kill each other. If a person believes in the kenotic theory of Christ, then that person must, of logical necessity, reject all conflicting positions. To hold that imputed righteousness alone is salvific demands denial of all theology that includes imparted righteousness as meritorious. Belief in any deity automatically renounces all purely materialistic worldviews.
Religious beliefs, of course, aren't peripherals, such as one's preference for Impressionism over Cubism, Dmitry Shosta-kovich over Dizzy Gillespie, or (like Tolstoy) Uncle Tom's Cabin over King Lear. They are, instead, the most important and fundamental of all human beliefs, the first principles from which whole peoples and nations derive their identity, purpose, and meaning. Thus, when you hold fundamental and crucial theological positions that cannot be true without another's fundamental and crucial theological positions being false, then implicitly you are a personified rebuke to all that's (for them) sacred. You never have to challenge their beliefs openly; your mere existence is an affront.
Formal logic, then, explains religious bigotry and persecution. Jesuit Robert Parsons in Elizabethan England, with rigorous consistency, argued that if a person is convinced that his faith is the only true one, then "it followeth necessarily that he must likewise persuade himself that all other religions besides his own are false and erroneous; and consequently all assemblies, conventicles, and public acts of the same [persons] are wicked and dishonorable to God," and must be stopped by whatever means necessary. Lest one believe this intolerance was merely a Catholic problem, Martin Luther once said, "I can no wise admit that false teachers should be put to death. It is sufficient to banish them." However, a year later he changed his mind: the sword, he urged, must be used against heretics.
Religious faith, by seeking to explain the ultimate reality into which all else can be resolved and which itself cannot be resolved into anything else, doesn't--by sheer logical necessity-- easily tolerate contraries. Certain "truths" automatically exclude the possibility of others; what "is" inherently implies what "isn't." And when truth--which by its very nature is exclusionary-- excludes the premises upon which people build their worldviews, tolerance (for lack of a better word) becomes illogical. "Tolerance in religion," wrote Reinhold Niebuhr, "frequently means an irresponsible attitude toward the ultimate problem of truth."
There is, however, one way around intolerance as an analytic predicate of religious faith--and that is if (and only if) inherent in that faith is the fundamental acceptance of those who hold contrary religious beliefs.
Though Christian history mocks the notion, the Christian faith does have that teaching built into its very fabric. Jesus said that "Thou shalt love thy neighbor as thyself" (Mark 12:31) was the second of the two greatest commandments. With the exception of the first (loving God with all your heart), one can't get more basic than second. Thus, loving even those whose views oppose yours is about as fundamental as fundamental Christianity can get. Indeed, Christ's command didn't say, "Love your neighbor as yourself, just as long as your neighbor doesn't hold teachings that contradict yours." On the contrary, Christ's cryptic statement, without any qualifications, means, "You shall love your neighbor as yourself, even if that neighbor holds beliefs that can't be true without your beliefs- including the one to love your neighbor as yourself--being false."
Jesus never said to love your neighbors beliefs, only your neighbor--a big difference, one that would have changed the course of Christian history had those who thought they were following the first great commandment by violating the second understood that only by keeping the second were they keeping the first.
Until that truth, that of loving even those whose fundamental views conflict with your own, becomes a practical reality in the lives of the faithful, religious intolerance will follow religious belief.
Anything else would be, well, illogical.