I fear it's because religion is man's attempt to reach God, and when he feels he has succeeded, he cannot abide anyone else's claim to have done the same.
“It is in Rousseau's writing above all that history begins to turn from upper-class honour to middle-class humanitarianism. Pity, sympathy and compassion lie at the centre of his moral vision. Values associated with the feminine begin to infiltrate social existence as a whole, rather than being confi”