We're not conjuring them up, like the witch of Endor, or engaging in two-way conversation.
We're asking them to pray to God for us.
Rev. 5:8And when he had taken it, the four living creatures and the twenty-four elders fell down before the Lamb. Each one had a harp and they were holding golden bowls full of incense, which are the prayers of God's people.
It’s irrelevant.
Contacting the dead is contacting the dead.