The most lethal, but most wholesome, depending on the ideology, are doctrines

History shows, nothing is more lethal than rationalizations, in which one group demonizes another, for example Nazi ideology, current Jihadist, and truth be told, general Islamic doctrine toward infidels; but simultaneously, nothing is more wholesome then doctrines that highlight unity, for example, Chassidus / Judaism that underscores how everyone and everything are unified in their shared purpose of serving their Creator, thereby bringing hearts together as well as being forces for love and kindness!