I think there's a degree of some people being maybe genetically predisposed to having more serious adverse reactions to trauma as well. An obvious example is when it leads to psychosis. So the objective reality of what happened is not necessarily the only thing which factors into how it affects somebody's functioning.
I don't disagree with that at all, but I do think that line of thinking about ones own issues can lead to a sort of self-blame - thinking things like: if I were stronger I wouldn't have been hurt by that neglect or mistreatment. No question, who you are has a huge impact on how something effects you, but nobody reacts well to e.g. neglect or mistreatment. I might end up with depression, while my sibling ends up with anxiety. That's our predisposition interacting with the objective reality, but neither outcome shifts the blame for the neglect or mistreatment to us. I know that's probably not what you were trying to say, but I do think that idea is one possible place downstream of what you are saying.