This quote is attributed to Matilda Joslyn Gage, a women's rights activist, and of all things, a staunch critic of religion and advocate for separation of church and state.
Was this quoted in wts' magazine or is this a different publication? Seems about right for wts, who misquoted Sagan to support their creation theory.
Sympathetic contagion, generally connected with some religious feeling, never has force where the intellect is scientifically and philosophically cultivated, and active. It belongs to an age, or a phase of ignorance and religious superstition. The crusades dragged thousands from home to engage in a war for wresting the Holy Sepulchre from the Turks. For three centuries, imagining they were doing God's service, men were afflicted with that superstitious madness till even children entered it, and thousands of boys and girls from ten to fourteen years of age, led by one of their own companions, marched despite parents and magistrates, on this same mad errand. Moral contagion as a law of life, has never yet received its due consideration. From such instances as have been mentioned, one can well see how Bishop Butler came to suggest his famous idea of the insanity of whole communities. He deemed many incidents of history unexplainable on any other grounds. Delusions seem to be capable of communicating themselves and fastening with a very tenacious hold upon the imagination. During the witchcraft delusion, many persons voluntarily accused themselves of its practice. At the time of the Tarantula mania, which raged in the south of Europe during the fifteenth century, whole companies of the afflicted, hand in hand, sang and danced themselves voluntarily into the sea and were drowned. Suicide, crime, and even accidents put on a contagious form. No stranger fact exists in the religious history of the world, than the rise and spread of the Mormon delusion in this country. The one man power, contrary to the instincts of our government, swelling in the space of thirty years from nothing to one hundred thousand; the deeper depths of woman's degradation, hand in hand, with this autocracy, furnish a problem whose cause is for the philosophers to elucidate. ("The Woman's Anti-Whiskey Crusade," The Golden Age, 21 March 1874.)