I'd venture to say that for a shy person the difference isn't necessarily that large, I can understand missing social cues when you are constantly ignoring warning signs just because you are out of your comfort zone.
(that said I will never understand nor defend the scenarios depicted in the article)
I'd venture to say that for a blind non-participant the difference isn't necessarily that large.
Meanwhile, aggression covers a lot of ground, which includes clubbing someone over the head, and generally being a jerk. But the fact that someone uses this word with two "g"s and two "s"s to describe some part of the process of building a happy family does not mean that other people are going to automatically know how to build a happy family after having read the paragraph that uses those words...
(that said I will never understand nor defend the scenarios depicted in the article)