Because the Bible said all DIE once. She died. She is in the grave. Her soul is in heaven. She is NOT sitting at the right hand of God, only Christ is. She ain’t appearing to people. That is demonic demons doing that. Not true Mary. Mary has nothing to do with salvation. The Bible MAKES IT CLEAR that ONLY through Jesus Christ do you get to heaven. Not through Mary.
What happened to the at least two deaths of Lazarus and all those who rose from their tombs during the crucifxion??
But Christ has indeed been raised from the dead, the firstfruits of those who have fallen asleep. For since death came through a man, the resurrection of the dead comes also through a man. For as in Adam all die, so in Christ all will be made alive. But each in turn: Christ, the firstfruits; then, when he comes, those who belong to him. Then the end will come, when he hands over the kingdom to God the Father after he has destroyed all dominion, authority and power. For he must reign until he has put all his enemies under his feet. The last enemy to be destroyed is death. For he “has put everything under his feet.” Now when it says that “everything” has been put under him, it is clear that this does not include God himself, who put everything under Christ. When he has done this, then the Son himself will be made subject to him who put everything under him, so that God may be all in all. (I Cor. 15:20-28)