We all choose what we will believe and what we will not. If you were to pass away and your close relatives gave permission to allow the church baptize you vicariously, we would do it. We don't go off of what an individual believed in this life but allow them the possibility to have changed their mind once in world of spirits. Like I have stated several times before, it is in the spirit world where you will have to make your final decision. There you can reject it and it will not be binding upon you and will have no effect.
I am a spirit, I am in the spirit world. I am with the Lord. Your claim is that as a spirit I would have to look to someone back on earth to make things right for me. Why? Because those in the spirit world (including the Lord) have no power? You, not the Lord, have the power? (And some get upset that I label this as a kind of idolatry.)
You may not recognize it, but Catholics and LDS are close in respect to those who have passed on. We pray for those who have passed on, and I know, absolutely, those prayers have power. Not once have I had to be a proxy to anyone to have these prayers heard. I do not question what is in your hearts; I do question your lack of reverence for the freedom of will God bestowed on each of us. Unless your LDS Church has MY authority for you to become MY proxy, no relative, no matter how close has any authority to turn me over to one of your proxies. For this reason alone, your ceremonies are invalid. Then an LDS statement here that the spirit in the afterlife can just reject your rite after it is done is an admission that the LDS church has no respect for its own rituals since they say outright that ritual can be shunned once done. It is an admission your rituals have no power. We agree on that point as well.
So why not leave it with prayer and acknowledge the power of prayer and the results are in the hands of the Lord.
In the last words of the Old Testament it says,
Malachi 4:5-6
5 Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the Lord:
6 And he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse.
Elijah has come and has turned the hearts of the fathers to the children and the hearts of the children to their fathers. This return was fulfilled in a visitation to Joseph Smith in April of 1836.
Doctrine and Covenants 110:13-16
13 After this vision had closed, another great and glorious vision burst upon us; for Elijah the prophet, who was taken to heaven without tasting death, stood before us, and said:
14 Behold, the time has fully come, which was spoken of by the mouth of Malachi—testifying that he [Elijah] should be sent, before the great and dreadful day of the Lord come—
15 To turn the hearts of the fathers to the children, and the children to the fathers, lest the whole earth be smitten with a curse—
16 Therefore, the keys of this dispensation are committed into your hands; and by this ye may know that the great and dreadful day of the Lord is near, even at the doors.
This dispensation that we currently live in is known as the dispensation of the fullness of times. In this dispensation, the prophets of all other dispensations from times past would commit the keys of their dispensation to the current prophets of this dispensation. Elijah restored the keys of his dispensation to the Prophet Joseph Smith and part of those keys was the turning of the hearts of the fathers to the children and the hearts of the children to the fathers. This is being fulfilled as we of this dispensation are looking back into the past at our forefathers and collecting all their names so that they can receive the saving ordinances that are performed in our temples including baptism for the dead. We believe that during the millennium the heavens will be opened and all the information about this earth's past inhabitants (from the fathers) will be revealed and all those who desire to have their work done will have it done. This is the fulfillment of Malachi's prophecy. For now, the heavens are not open to us and we now baptize anyone whom we can gain permission to baptize. It is not far distant when our Lord will come again on the earth and at that time the first resurrection will occur, but before one can enter into the kingdom of heaven, they must be baptized. Thus the immediacy of the work. The first resurrection lasts throughout the millennium. The Lord is establishing his temples for the great millennial work that has already started.
God has commanded us to build temples and within those temples we are to place baptismal fonts for performing the great work for the dead. For this reason we do not simply ignore him but we seek to do his will. God does not want it to be just left up to him through our prayers but has instructed us to go forth and do the work.
We recognize your authority since you are here on the earth to decide for yourself whether to be baptized or not. But once you have a change of existence and find yourself in the world of disembodied spirits, we don't know if you will change your mind or not. We simply perform the ordinance in case you do change your mind and allow you to accept and reject it then when you are presented again with that choice. Perhaps when the heavens are opened in the millennium, we will know who decides to accept it and who decides to reject it before performing the ordinance. But for now we don't have that luxury and must do all we can for the salvation of mankind as God would have us do.