The problem with that is the scriptures testify the Atonement was for every and all men:
Mormonism teaches that the atonement is only an opportunity; full salvation requires Mormons to obey ALL the laws and ordinances of Mormonism.
Mormons are required to proxy work for the dead.
During the final months of his life, the Prophet Joseph Smith reflected frequently regarding the importance of vicarious ordinances for the dead. In fact, he considered work for our ancestors to be so important that he taught “their salvation is necessary and essential to our salvation . . . they without us cannot be made perfect – neither can we without our dead be made perfect.”
 Doctrine and Covenants 128:1
 Doctrine and Covenants 128:15