Thanks Finkelstein.
When bad things happen in the world people want answers, and someone coming along with direction (and showing a keen interest in them) is like a breath of fresh air for many, especially the vulnerable. Any audience these self appointed gurus gain leads to feeding the ego, and ultimately deluding them into feeling special/elite. This feeling keeps them driven so much that losing control over the "disciples" becomes a threat to their fake identity, hence the propaganda (either self believed or outright lies) to keep people in line.
"Don't go elsewhere, you need me".
They jealously and arrogantly guard what they see as their "property". Mix in some truths to sound plausible, pepper in some nice things, reason in circles, spin/ignore the negatives, keep making more followers...rinse and repeat. Pack it neat and tidy, label the box "The Truth" to make it easier to sell.
----------
On the one hand claiming to have exclusive rights to "The Truth" sounds crazy and arrogant to most reasonable people (and what puts them off). However, on the other hand it's actually a very good sales ploy. Can you imagine trying to advertise something as having mediocre results?
"Come and try this new product, it may work, or it may not, it's pretty much the same as all the rest out there!"
Would you buy that? Hardly. Come at someone with something "original" and "authoritative" (THE Truth...this is almost Divine, not just bible commentary) and suddenly you have someone's attention (or at least the person who's more open to exploitation).