I put it down to simply marketing, and like anything, doctors will attempt to market "their" brand of therapy, some offshoot to some existant therapy that they want to try and become rich from, instead of focusing on not money, but instead the patients themselves. There are many types of therapy and techniques in the world to treat people, most of which are merely offshoots of an actual main therapy, but the facts remain that to help PTSD, the primary beneficial therapy is one that provokes the mind itself, and one where the sufferer must experience for themselves, ie. CBT, exposure therapy, mental imagery, any type of technique that actually involves the person or provokes their brain in direct relation to their trauma.

Basically, if any technique is trying to disregard the trauma, or trying to bandaid it, the long term effects have been proven over and over again with PTSD treatments already, and they failed to provide substantial long term benefit to the sufferer. CBT is the primary treatment for PTSD because of its long term effects, being it gives better long term effects for the patient than any other technique currently. Why? Because the sufferer must learn and educate themselves to why things are happening, what is going on within them, etc etc... knowing what is happening allows each person to help themselves uniquely, where no blanket treatment works effectively for PTSD... tried and proven, scientific results already state it.