Oh yeah. I bring up those descriptions to illustrate that sensitivity is often seen as a fundamental trait of the type.
Intellectual arrogance and distancing from the world as a form of self-protection from encroachment and intrusion and all that. Hell, at the relatively-naive-but-still-useful 10,000 foot view, all of the Enneagram types can be said to boil down to coping mechanisms for certain sensitivities. Whether the notion of sensitivity is "objectively true" (c'mon, we're talking about typology) is secondary for me; all I know is that it has some personal significance and so I embrace it.
The emotional origins also may not be true for all people--it's just one person's description, after all--but it did happen to ring true for me. I work with a lot of researchers, but I'd only peg a few for sure as 5s. The 5-est 5 I know told me that he quickly learned to fend for himself, coming home to an empty house and making his own snacks, and so on. That's similar to my upbringing; attention and help was focused in places other than me, and I felt rejected, so I learned not to expect or ask for help or friendship. My ego hinged on self-sufficiency and gaining enough competency to properly deal with the world myself.
Like any coping mechanism, that only took me so far. I'm mostly past all of that business, but I still don't like being imposed upon, and that tendency still going to color my interactions with the world and with other people to some extent.
Now that the world isn't so frightening, bridging the gap and gaining trust is key for me. Completely intellectualizing this for a moment--I gauge out potential alliances in general or with specific issues, and I fare better with people who are able to communicate beyond the level of "just words" and are smart enough to realize (or at least think about), in general, what is really going on.
In general, I do allow myself to develop emotional connections, and I've embraced my strong empathetic streak.
I've gotta make a mental note to look at Boundaries theory..