The question was put:
"If Baptisms For The Dead Are Fake, Phoney And Of No Effect, Why Do People Care?"
To which I responded:
I can think of some reasons, even though I don't consider them to be valid:
1) Superstition. Inasmuch as some people imagine that good people doing good things for others' souls after they die (i.e., praying, making offerings dedicated to that dead person's salvation) will do good for that person's soul, some people likewise imagine that purporting to do an act for that same soul which people perceive to be evil (i.e., baptizing them into that darned false religion called Mormonism founded by John Smith) will somehow harm that soul in the afterlife. Both are quite ridiculous in my opinion, because I believe that, ultimately, only each individual has stewardship over their ultimate destiny and salvation, and no other person, whether it be a friend, an enemy, a relative, God, or the devil, can force someone into or out of heaven.
2) Not wanting to grant a perceived victory to a false religion. Some opponents of the LDS faith probably get sick and tired of hearing the claims Mormons make about baptizing the dead into their faith. They see these perceived successes as emboldening LDS members and giving the LDS accomplishments to tout when proselytizing and selling the church's image in the media. Obstructing the church's efforts to baptize the dead helps put a wrench in the church's overall mission.