Here’s John Stuart Mill,my favourite genius, speaking of his father’s views on religion:
…he regarded it [religion] with the feelings due not to a mere mental delusion, but to a great moral evil. He looked upon it as the greatest enemy of morality: first, by setting up factitious excellencies,—belief in creeds, devotional feelings, and ceremonies, not connected with the good of human-kind,—and causing these to be accepted as substitutes for genuine virtues: but above all, by radically vitiating the standard of morals; making it consist in doing the will of a being, on whom it lavishes indeed all the phrases of adulation, but whom in sober truth it depicts as eminently hateful. I have a hundred times heard him say, that all ages and nations have represented their gods as wicked, in a constantly increasing progression, that mankind have gone on adding trait after trait till they reached the most perfect conception of wickedness which the human mind can devise, and have called this God, and prostrated themselves before it. This ne plus ultra of wickedness he considered to be embodied in what is commonly presented to mankind as the creed of Christianity. Think (he used to say) of a being who would make a Hell—who would create the human race with the infallible foreknowledge, and therefore with the intention, that the great majority of them were to be consigned to horrible and everlasting torment. The time, I believe, is drawing near when this dreadful conception of an object of worship will be no longer identified with Christianity; and when all persons, with any sense of moral good and evil, will look upon it with the same indignation with which my father regarded it. My father was as well aware as anyone that Christians do not, in general, undergo the demoralizing consequences which seem inherent in such a creed, in the manner or to the extent which might have been expected from it. The same slovenliness of thought, and subjection of the reason to fears, wishes, and affections, which enable them to accept a theory involving a contradiction in terms, prevents them from perceiving the logical consequences of the theory.
—from Christopher Hitchens’ delightful book, The Portable Atheist. This is from Mill’s Autobiography, which was published only after his death in 1873.