As someone who was abducted and kidnapped at gun point, PTSD and trauma are experienced differently by different people.
PTSD/trauma may be the result of being victimized, but it is not “learned” any more than a bone might “learn” to break under stress.
What happens under extreme trauma is an onslaught of electric signals and chemical reactions in the brain, essentially adrenaline (fight or flight) and cortisol (stress) responses. They help you survive when needed, but terrible for the brain and body in extreme amounts and/or prolonged exposure.
The issue is not that it is “learned” but that in some people the trauma essentially fires otherwise dormant pathways in the brain and instead of these pathways going back to a dormant state the neurons and pathways are potentially strengthened by the single acute episode and remain turned on. It creates an awful feedback loop where these neurons and pathways fire from normal/non traumatic stimulus moving forward because the connections become so strong they become a default pathway. Then regular firing of these pathways just reinforces the connections. You could point to that as “learning” I suppose, but it is involuntary. The associated behaviors are commonly avoidance in order to prevent these misfirings but unable to avoid it the responses will usually be consistent with the original response to the adrenaline and cortisol during the trauma.
Not everyone responds the same, because it really isn’t learned but something I would describe more as a physical “injury” to the brain from the natural biological response to the trauma. The 4 pillar model of the article might encapsulate a decent general framework for trauma victims, but it entirely ignores the very real biological responses and physical effects of trauma, so is on par with saying stress and fight or flight responses are learned. If it were learned we would teach soldiers not to have those responses, instead they are trained to manage their reactions to those responses, and even with training trauma can not be prevented in all individuals in all situations.