Steve... Like all Socionics information elements, Se has nothing to do with so-and-so getting mad, as you're trying to make it seem here.
Like all info elements, Se is something you can see in behavior and feel psychologically.
In Se egos, Se is something you see manifested in someone's personality continually, i.e. nearly all the time... (Like Ne in your ego and Fe in mine...) Thus, "Se leading."
Maybe you're right, Steve, and the 'why' of someone's personality = enneagram... That is irrelevant to Socionics, as 'why' is not what Socionics seeks to describe. (Personally, I think 'why' is much more complicated than the enneagram presents it.)
Socionics describes personalities via how they process info... The only way one can detect how people process info is by observing their personalities, (e.g. psychological "traits,") to see and feel how the info is manifested in their personalities. ("Manifested" = what you can see and feel it in a person's personality.)
To extend your color example to Socionics and the real world--just as I don't give a shit "why" e.g. purple wants to be purple (lol; ) I don't particularly give a shit why Se wants to manifest in certain people, (i.e. what the enneagram describes.)
I am a practical man and thus content to know Se (and the color purple, for that matter,) when I see them and feel them, i.e. I am content with Socionics, unpolluted by the enneagram.
This is all by way of saying, you and Socionix are abstracting Socionics--something meant to be tangible and experiential--to the point of being impractical, ineffable, and signifying next-to-nothing to real people in the real world.