Melchizedek Priesthood
"Through the authority of the Melchizedek Priesthood, Church leaders guide the Church and direct the preaching of the gospel throughout the world. In the ordinances of the Melchizedek Priesthood, "the power of godliness is manifest" (D&C 84:20). This greater priesthood was given to Adam and has been on the earth whenever the Lord has revealed His gospel. It was taken from the earth during the Great Apostasy, but it was restored in 1829, when the Apostles Peter, James, and John conferred it upon Joseph Smith and Oliver Cowdery
LDS.org on mormon belief on Melchizedek Priesthood
From sevenbak: Currently three different types of recommends are given: (1) for members to receive their own Endowment, to be sealed to a spouse, or to be married in the temple for time only; (2) for members who have received their Endowment to participate in all temple ordinances for the dead (see Salvation for the Dead); and (3) for unendowed members to (a) be baptized on behalf of the dead, (b) be sealed to their parents, or (c) witness sealings of their living brothers and sisters to their parents. The same standards of worthiness apply for all recommends.
FROM: The Redemption of the Dead and the Testimony of Jesus
"The doctrine that the living can provide baptism and other essential ordinances to the dead, vicariously, was revealed anew to the Prophet Joseph Smith. He learned that the spirits awaiting resurrection are not only offered individual salvation but that they can be bound in heaven as husband and wife and be sealed to their fathers and mothers of all generations past and have sealed to them their children of all generations future. The Lord instructed the Prophet that these sacred rites are appropriately performed only in a house built to His name, a temple.
The principle of vicarious service should not seem strange to any Christian. In the baptism of a living person, the officiator acts, by proxy, in place of the Savior. And is it not the central tenet of our faith that Christ’s sacrifice atones for our sins by vicariously satisfying the demands of justice for us? As President Gordon B. Hinckley has expressed: “I think that vicarious work for the dead more nearly approaches the vicarious sacrifice of the Savior Himself than any other work of which I know. It is given with love, without hope of compensation, or repayment or anything of the kind. What a glorious principle.”
Some have misunderstood and suppose that deceased souls “are being baptised into the Mormon faith without their knowledge” or that “people who once belonged to other faiths can have the Mormon faith retroactively imposed on them.” They assume that we somehow have power to force a soul in matters of faith. Of course, we do not. God gave man his agency from the beginning. “The dead who repent will be redeemed, through obedience to the ordinances of the house of God,” but only if they accept those ordinances. The Church does not list them on its rolls or count them in its membership."
The MAIN task of the LDS temples...baptism for the dead.
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Good try at a miss-leading thought.
All of God's children are given the opportunity to have all of the ordinances God has declared we need. (yes, that is an ‘s’ as in plural, as in not just one ordnance)
Not just Baptism's for the dead.
Easy information for anyone who wants to know.
And the people for whom the ordinances are performed have the option to accept or not accept them in the next life.