I will agree with you on this. However, in my case, I did studdy with the best teachers I could find, and traveled all over the world to find and learn from them. I did not worship any sat-gurus exclusively, instead learning from several masters. I'm sure glad I did so now, because not only not one of these generally recognized healers was able to help me but I'm finding out they belonged to counterfeit spiritual systems. My involvement in them might have given some legal ground for demons to enter my body. I found Jesus Christ the most effective healer of all; in his holy name I'm able to fight off the voices.
God bless!