If you read that entire thread, posted by another member, now 10 years ago when EMDR was just making headway into trauma, EMDR was causing levels and forms of brain damage to persons self reported. If you research a little harder, you will find there have been quite a lot of people temporarily / permanently damaged by inexperienced therapists at that time, running off with EMDR and doing it wrong. The result had caused death to some people by suicide, due to being overwhelmed. Therapy does this still today, nothing new there. There are many reports by people who have had EMDR reporting different levels of brain function concern due to EMDR by inexperienced delivery.
It was a problem then, and prior, and progressively got better. You aren't putting it in context of the entire discussion, you're taking snippets, as mentioned above, then wrapping your own belief system / knowledge that brain damage equals vegetable. What does that even mean? PTSD causes certain forms of brain damage that they do not yet know how to undo. Are you a vegetable because you have PTSD? In the sense that I think you're using vegetable to say that brain damage means loss of all faculties -- you need to do a lot of research and probably get a more accurate term based on science today.
The member becvan of that thread talked about now having temporary / permanent memory problems that she didn't prior to an inexperienced, over-excited, therapist unleashing techniques upon her without full understanding of her history or implications. The therapist was at fault. EMDR was very new then. Further members added similar experiences. You can search the web for plenty of negative outcomes from EMDR, most therapies actually, and the problems a person now has as a result.
All claims I've ever read, were due to the therapist being at fault. Doing things with a technique without being experienced. Modifying techniques without care or concern of the outcome. Not doing due diligence in prior lead work to ensure they weren't going blind into repressed memories or other such problems that EMDR is known for over-flooding complications. If the therapist believes a client isn't being totally honest, they should not shift into EMDR, instead see what pops out -- there are better present centred therapeutic techniques for use that can be controlled better if flooding occurs where it shouldn't.
EMDR is one of the harder qualifications to obtain in therapy, and for good reason, because of all the issues discovered with the delivery, they made it harder to get the qualification into your own practice. You do considerable training today to be an EMDR therapist, compared to any other technique. You didn't 10 years ago. Why? Because EMDR has such potential to go very wrong, very quickly, in unexperienced hands. All techniques have this capacity, EMDR is a little more blind sided though due to the delivery technique using distraction.
EMDR is a good therapy for treating trauma. That does not mean it hasn't had a wonky history getting to where it is today. It has... and you can research its history yourself. There is still, to date, zero factual evidence to support eye movements impacting treatment efficiency for EMDR. EMDR has been categorised as an exposure treatment, contrary to the claims by Shapiro herself.
You can read a little about its history at
EMDR Treatment: Still Less Than Meets the Eye? from a 1996 scathing review, then updated in 2011 with closer to what we now know and the effectiveness of EMDR today for trauma.
We with the severe levels of PTSD have certain levels of brain damage. Still not a vegetable though! Neuroscience has additionally proven our brains are quite malleable and plastique, that our brains create new neuronal pathways and cells, even though others have died / been damaged.
I think you need to relearn a better term, one that is not so offensive, IMHO. Brain damage does not make a person anything other than the impact of the damage itself. Mental health. Talk with any TBI sufferer -- pretty sure they do not cite themselves as vegetables and can function fine in many aspects of their lives -- they merely struggle in some areas due to the damage incurred.