Ptsd is a learned reaction. Who says its permanent?! The brain is very malleable.
Disagree - Experts still debating that one - Agreed.
Experts don't know what PTSD actually is at this point, other than it isn't a chemical imbalance, agreed that is the pharmaceutical mythical explanation to sell you their drugs. They know its focus seems to reside within the pre-frontal cortex. Beyond that, PTSD cannot be stated as a learned reaction or otherwise, until such evidence proves such. Is some of PTSD environmental (learned reaction)? Absolutely based on meeting criterion A alone. Is it completely environmental? No such credible evidence cites this in any information I'm reading from the worlds best in traumatology.
Permanent! Well... I think there is a split in that type of discussion between PTSD and symptoms. You can heal symptoms and remove them completely, for a majority. Then you have to look at PTSD the illness, cured or incurable, comes back to the above paragraph that they don't know enough about it to make such determinations at this time. The experts can't definitively even state what exactly it is to make such a statement either way. What they know is that prior exposure causing PTSD symptoms statistically puts the person at a higher susceptibility that those symptoms will return if faced within another trauma versus a person who doesn't show such severity.
Science is excelling, though it is far from concluding exactly what PTSD is at this present time. They still can't rule out genetics, and at this time, genetics are a definitive within PTSD, thus that immediately removes that PTSD is a learned reaction from the table. Behaviour is an influence, though genetics are scientifically still foundational within the mental health argument. To what degree I do not know, nor do the experts it seems.
Is the brain malleable? Absolutely agree... hence symptoms can be healed for the majority of sufferers.