Her posts make sense to me. It sounds like you're defining 'nurture' purely as 'environment' (which...yeah, that's what it normally means) while OrangeAppled is defining it as what one experiences, which is dependent on both your environment and your inborn temperament. So she's drawing a distinction between 'set at birth' (preferred cognitive functions) and 'arising as a result of life experiences' (enneagram motivations).
Not to be pedantic, but if people are going to use terms other than in the accepted sense, they need to supply revised definitions, or use a more appropriate word, not turn around and ignorantly suggest that someone else's reading comprehension is at fault, when it's really their failure to define their terms that may be creating misunderstanding.
But in fact, she
is using the term in the traditionally accepted sense - hence the use of the expression "nature vs nurture" which implies mutual exclusivity.
Whereas, in reality it is more like nature via nurture - gene expression is very much influenced by environment. But there are limits to the effects of environment.
So, to use your example earlier, even if someone is set at birth to be overwhelmed by ordinary emotional stimulation, the type 5 motivations to withdraw and detach may still develop as a result of experiencing that sense of overwhelm, that feeling of intrusion, rather than being present all along.
I don't see that as being a useful distinction. The
potential is present all along. That's all Nature means. Genes encode potential. They almost always have to activated in some way by the environment.
I see this stuff in terms of thresholds. If a person's nervous system is so calibrated that exposure to a normal amount of stimulation is experienced as overwhelming - that is Nature, pure and simple. Sure, maybe if they spent their whole life in a flotation tank, they'd never be overwhelmed - but it's not useful to construct unrealistic scenarios like that.
What is the root cause of this over-sensitivity? Is it environmental (early trauma) or genetic (innate (in)tolerance)? The former is Nurture, the latter is Nature (reinforced by Nurture).