His history is solid. However, there are people who believe Gunderson was a FBI plant to identify any extremist elements of the conspiracy/anti-government movement. Some people believe he meant well but was misguided and was misinformed. Now normally I wouldn't care what people think but one of those people happened to be Bill Cooper.

His exact quote is:

"Those who are attracted to the Mysteries who are unable to grasp the esoteric meaning of their education often take the exoteric interpretation to be truth. They often turn to Satan or Lucifer (Light) as their object of worship never understanding the metaphor for a much deeper philosophy. These Satan worshipers are useful. They furnish a diversion and are often a source of large sums of money. The Brotherhood has seldom found itself lacking in fools or funds. Ex-FBI operative Ted Gunderson is the hegelian tool in this instance pointing you off after Satanists, a cull-d-sac where you will chase your own tail round, and round, and round. I do not believe that Ted knows that he is being used in this regard. I may be wrong." to be found at:

http://www.williamcooper.com/majestyt.htm

That quote has actually turned prophetic in light of the Pizzagate scandal.

Edit: I just watched the video. I realize now that he isn't a plant. I read counter intelligence websites which seek to discredit him. As for Cooper's criticism; Cooper is deep into the esoteric. He must have not wanted his followers to get distracted looking for Satanic Cults rather than focusing on the Esoteric information.