In today’s world, where truth is relative and anything goes, I can understand why the idea of almost everyone getting to go to heaven would be attractive.
From
catholic.com/library/Distinctive_Beliefs_of_Mormon.asp
Mormonism teaches that practically no one is forever damned to hell. Aside from Satan, his spirit followers, and perhaps a half-dozen notorious sinners, all people who have ever existed will share in heavenly “glory.” Not, mind you, all in the same heaven. There are, in fact, three heavens.
The lowest heaven is populated by adulterers, murderers, thieves, liars and other evil-doers. These share in a glory and delight impossible to imagine. Their sins have been forgiven, and they now enjoy the eternal presence of the Holy Ghost.
The middle heaven contains the souls and bodies of good non-Mormons and those Mormons who were in some way deficient in their obedience to church commandments. They will glory in the presence of Jesus Christ forever.
The top heaven is reserved for devout Mormons, who go on to become gods and rulers of their own universes. By having their wives and children “sealed” to them during an earthly, temple ceremony, these men-gods will procreate billions of spirits and place them into future, physical bodies. These future children will then worship their father-gods, obeying Mormon commandments, and eventually take their place in the eternal progression to their own godhood.
Mormons think this doctrine is a strong selling point. They point out (erroneously) that only their church offers families the chance to be together forever in eternity. But read the fine print. The only way you can have your family with you is if each one of them has lived a sterling Mormon life. Otherwise, a spouse, parent, or child may be locked forever in a lower heaven. Indeed, the faithful Mormon wife of a lukewarm Mormon man will leave him behind in an inferior place while she goes on and is sealed to a more devout Mormon gentleman. These two will then beget and raise their own, new family.
The LDS slogan, “Families are forever,” means fractured families.