We never did teach that, so far as I know. Joseph Smith, quoting God, said that the creedal statements of the churches were abominations, for the reason explained in Post 126. This is not to say that we consider all of the beliefs and practices of other churches to be abominable.
In my previous post, I quoted Joseph Smith and Gordon B. Hinckley. Here is what Brigham Young was quoted as saying:
"Mormonism" so-called, embraces every principle pertaining to life and salvation for time and eternity. No matter who has it. If the infidel has got truth it belongs to "Mormonism." The truth and sound doctrine possessed by the sectarian world, and they have a great deal, all belong to this church. As for their morality many of them are morally just as good as we are. All that is good, lovely, and praiseworthy belongs to this church and kingdom. (Journal of Discourses 11:375).President Young was also quoted as follows:
It was the occupation of Jesus Christ and his Apostles to propagate the Gospel of salvation and the principles of eternal life to the world, and it is our duty and calling, as ministers of the same salvation and Gospel, to gather every item of truth and reject every error. Whether a truth be found with professed infidels, or with the Universalists, or the Church of Rome, or the Methodists, the Church of England, the Presbyterians, the Baptists, the Quakers, the Shakers, or any other of the various and numerous different sects and parties, all of whom have more or less truth, it is the business of the Elders of this Church (Jesus, their elder brother being at their head,) to gather up all the truths in the world pertaining to life and salvation . . . (JD 7:283).
They did teach that.
When did the teaching get officially reversed? Have any citations?
Just SOME?