In western spiritualism, there is a need for something called "channeling". The souls recruited by necromancy are possessed by psychics, which means that the behavioral language of psychics has been replaced by the souls of necromancers. The dialogue between man and psychic is the dialogue with soul. I believe everyone has had such an experience. If you were scared when you were young, adults would "scream". This call is to call back our frightened souls, which is obviously a superstitious practice.
Another important reason why Christians are so superstitious about necromancy is that there is a technology called necromancy in Africa. That is, if someone has offended, the offended person can find a warlock and let him turn the person who has offended himself into an obedient "corpse". It is called "corpse" because he seems to be dead and has no memory or consciousness, so he obeys his master's orders. In fact, it is only because the warlock gave him puffer fish poison powder, but Christians still believe in spiritualism.
Therefore, it is mainly the teachings of African religions that combine animism and spiritualism, so that their followers are convinced of spiritualism. This is a superstitious behavior. So far, most African teaching methods have been reasonably and scientifically explained.