It's uh not. That's kinda the extreme fantasy version of it. Necromancy in religion can be seen as just speaking to the dead. Or 'divining' answers from the dead.

It's seen not a great idea because you could be talking to anything. Demon, yourself, another entity, or whatever.

I think the parallel they were drawing was simply the fact when you "talk to the dead" it's not really them or "may not be".