Shamanism is indeed dealing with the spiritworld. But shamanism is not witchcraft (necessarily, although there are some schools of thought that suggest that witchcraft is the european equivalent of shamanism). Just because a dictionary suggests witchcraft and sorcery are the same doesn't necessarily make it so. Dictionaries have also been known to suggest of witches that they are:
A woman claiming or popularly believed to possess magical powers and practice sorcery.
A believer or follower of Wicca; a Wiccan.
A hag.
A woman considered to be spiteful or overbearing.
Informal. A woman or girl considered bewitching.
One particularly skilled or competent at one's craft: “A witch of a writer, [she] is capable of developing an intensity that verges on ferocity” (Peter S. Prescott).
(Also from dictionary.com)
Depending on which definition you go with, and none of the above are particularly accurate, will colour your understanding of what a witch does. A witch does not interact with and control demons and angelic beings (as a general rule) in order to aeffect change in accordance with will (useful definition of magic there) Were the dictionary definition of a witch to be written by someone who knows what a witch is 'cos they are one' there might be a better understanding here. Think about who compiles the dictionaries and their likely experiences of the world.
Where shamanism is concerned, the use of the term 'evil' to describe the spirits in the spirit realm is somewhat emotive. Certainly a Christian perspective would be likely to suggest that any spirit that is not the holy spirit is by default, demonic at source. Ok, that is a belief that fits with a Christian understanding of things. But the experiences I have had as a shaman would not suggest that all spirits in the spirit realm are 'evil'. Indeed very many are helpful in the battle against 'evil' spirits, and generally you will find that the shaman will be actively involved in battling with the 'evil' spirits. Now I imagine the Christian perspective would suggest that this is just a deception, and the shaman is battling evil spirits with evil spirits. But that just doesn't meet with my experiences.
I have also practised martial arts. The energy used in martial arts is human energy. It is energy inherent within human beings. I would imagine that from a Christian perspective, this could be seen as god given energy.
BB
Mike