I heard a story similar to this on NPR a week ago. I think it was Eli Wiesel who was upset about the planned baptism of Holocaust victims.
Is this offensive? If Mormons believe that they can offer someone eternal happiness through a posthumous baptism - which said person is free to accept or reject in Mormon theology - then why wouldn't Mormons do so? The issue here seems to be an inability to tolerate Mormon beliefs about the afterlife. Taking offense at the practice is essentially the same as taking offense at the belief.
As Catholics, we would have no room to criticize Mormons here, because we share an underlying conviction that our respective religion is objectively the greatest good for all people. Many people react to this claim with anger, and that's what you see in the responses to this proxy baptism thing.
The Mormons think that what they are doing is an act of love for the deceased. According to their beliefs the proxy baptisms they perform have no binding effect at all on deceased people unless these people choose to accept it sometime in the hereafter.The Mormons feel that everyone must be baptized to obtain the highest degree of glory in their multi-tiered heaven and such an ordinance must be performed on earth during a "mortal state" and cannot be performed after a person is dead by themselves. They go beyond this and do proxy "endowments" which is another ordinance as well as proxy temple marriages. All of these involve people acting as "stand ins" for the dead.
A mortal body must be involved and people (gender specific) can stand in as a proxy. I think Joseph Smith came up with the concept using one passage in the Bible:
I Corinthians 15:29, "Otherwise, what will those do who are baptized for the dead? If the dead are not raised at all, why then are they baptized for them?"
Personally I find this rather cryptic as I do not think there is historical evidence that people were baptized for the dead in Paul's era.
The Mormons often are surprised that people are offended, as they see this "work" as sort of a free insurance policy offered with no strings attached. I however can see how it offends some people for they perceive this as the Mormons claiming these people as converts, which is not really the concept.
I personally was subject to something similar. I was born into a Mormon family in a Catholic hospital. My mother told me when I was still pretty young that a priest had come around and baptized all the babies born the same day as me. I was not offended, figuring that it sort of "covered my bases" should the Catholics be right and the Mormons wrong on this subject. Later I would learn why Catholics believe in infant baptism, that the a person's soul is in great peril if they die before being baptized so they do it as early as possible to insure a possible place in heaven for all that they can. I came to think that the Catholics were simply doing me what they considered a favor, and I was actually touched instead of being offended.
When I was a teenager I went to a Mormon temple with a group of people my age and we all we part of being baptized for the dead. I was "assigned" four or five names of men who had died and whose details had been verified through the Mormons combing genealogical records. The names of ancestors of members of the LDS church generally stand in themselves (if they are "worthy" of getting the proper temple recommend). I had never heard the names before and most likely have never come across them again. I have no idea who they might have been. I guess it might even have been have been possible that they were Holocaust victims but that is quite unlikely.They were not singled out for any reason I can think of except for perhaps that the Mormons feel they have a special kinship with the Jewish people and they really wanted this proxy work to be available. The Mormon goal when I was one of them was to basically get the records of every single person that has ever lived and do this proxy work for them. I went through the baptism procedure with the name of the deceased people being spoken before I was dunked for each of the names. I would guess our group was involved with over 50 names that day, all supplied by a temple worker to the person doing the baptisms.
When I was a Mormon it was said that baptisms had been done for every deceased president of the US but one. From Mormon history lessons most of us assumed this must be Martin Van Buren, since he was often heavily criticized in our lessons for not aiding the Mormons when they were being persecuted. It is said that Brigham Young when hearing of this president;s death announced in a meeting that President Van Buren had died and gone to hell. Somebody was said to have remarked,"President Young, you shouldn't say that." Brigham then said, "You are right. President Van Buren has died and gone to hell, and I'm sorry." However, it was revealed that it more likely was Andrew Jackson due to a perceived genocide on his part.
It is a controversial subject that comes to a head very few years. No matter what is said by Mormon representatives they really, really want to baptize everyone that they can as they feel it is important to the persons who have died. I would guess that they would rather error of the side of causing offense than leave it all "undone."