No - ideology and religion can lead to war quite readily.

For example, your religion can proclaim that dark-skinned people are lesser humans (earlier-era Mormonism) or that anyone who draws a picture of the prophet must be put to death (many strains of Islam) or that anyone who does something faggy should be put to death (Christianity). Those extraneous rules encourage violence and warfare just as surely as leaving a pile of grenades in a schoolyard will encourage a nasty accident.