I think what OP meant was the following. Having two people with the same, positive aims (e.g. be a good parent, do your job well), the agency-driven one will achieve more with the same hard work as the another. Therefore, for people around you, you would wish them to be more agenty as a default.
These two concepts do not contradict each other. Unix can allow "doing stupid things" AND at the same time make them "difficult to impossible". So, the conclusion that Unix was misdesigned is not correct, at least not basing on your definition
I have taken the survey, also the extra part. Although I was never tested for IQ in professional way and since it was a question in the non-extra part, I assume that most LW readers were. Interesting observation (if true). Maybe it is a nationally dependent thing? This ad-hoc hypothesis can be validated by the survey if only enough people from enough countries take it