One popular writer within certain Catholic circles is Gabriele Amorth. He is an exorcist — not the “chief exorcist” that some people make him out to be — and he has used his work as an exorcist to judge and condemn many things from Harry Potter to unnamed Cardinals at the Vatican. He sees a Satanic conspiracy at work in the Church, and many people are quick to believe what he has to say. This is probably because they want to believe there is some sort of Satanic cult which makes the Vatican act contrary to their own ideas of how the Vatican should act.
Thankfully, another exorcist has taken up Gabriele Amorth and his claims. Fr. Jose Antonio Fortea Cucurull, who is not only an exorcist, but a theologian trained in the area of demonology, has pointed out in an article on Catholic Online that Amorth’s sources of knowledge are not credible because they rely upon two things: private, untested revelations and demons. The second to me is very telling.
Demons are going to be tricky. One of the first things an exorcist should know is not to trust them, not to believe them, not to let them get into your head. They can tell the truth, but they do not have to. And of course, they can take a little truth and distort it to make it into a lie. Indeed, as Fr. Fortea puts it in the Catholic Online article:
We can know with great confidence when a demon tells the truth in the subject directly related with the exorcism. That is, the number of demons, their name and similar things. But we cannot be confident in what regards concrete news relating to people.
When Fr. Amorth starts relying upon the evidence of demons to construct a Satanic conspiracy in the Vatican, I think we have evidence that Fr. Amorth has forgotten how dangerous it is to interact with demons and to believe whatever it is they have to say. Indeed, the more one talks with them to get knowledge from them, the more warped one is likely to become, and the more likely one is oneself going to be demon possessed. And even if one is not, one is at least playing around with demonic-magic.
As it stands, I really can’t tell what difference there is between Fr. Amorth’s knowledge from demons with that of John Dee. Fr. Amorth is playing with fire. I suggest we stand away and not get burned.
 This is not to deny the demonic — but such influences can happen without cults.