Yeah I read that quote recently, quite clever. The full quote was:
LDS philosopher Orson Whitney: Many years ago there came to Utah a learned doctor of divinity, a member of the Roman Catholic Church. I became well acquainted with him, and we conversed freely and frankly. A great scholar, with perhaps a dozen languages at his tongue's end, he seemed to know all about theology, law, literature, science and philosophy, and was never weary of displaying his vast erudition. One day he said to me:
"You Mormons are all ignoramuses. You don't even know the strength of your own position. It is so strong that there is only one other tenable in the whole Christian world, and that is the position of the Catholic Church. The issue is between Catholicism and Mormonism. If we are right, you are wrong; if you are right, we are wrong; and that's all there is to it. The Protestants haven't a leg to stand on. If we are wrong, they are wrong with us, for they were a part of us and went out from us; while if we are right, they are apostates whom we cut off long ago. If we really have, as we claim, the apostolic succession from St. Peter, there was no need for Joseph Smith and Mormonism; but if we have not that succession, then such a man as Joseph Smith was necessary, and Mormonism's attitude is the only consistent one. It is either the perpetuation of the Gospel from ancient times, or the restoration of the Gospel in latter days."
Of course I find it hard to believe that Jesus would come to the Earth only to condemn it to "centuries of darkness."
That is one among many other questions I can't wait to ask Him about. Until then, I simply trust He is doing what is best for those He loves.