So if not all people with that disorder are ENTJ, why is it used as an example for ENTJ behavior?
I'm not saying that you're wrong, I'm just saying that there's no way to know and that there are equally valid alternative explanations that wait to be tested before we can decide for sure. The shadow theory is one of those explanations proposed for personalities under stress. For example, it predicts that (http://www.teamtechnology.co.uk/myers-briggs/isfp.htm):
Now, I bet that this ISFP under stress exhibiting these symptoms would be seen as actually a very bad ENTJ. And there are reasons to think that many people in their professional life are *consistently* under stress and could be showing this behavior in a very regular way, even though it is not the "true" them.Under extreme stress, fatigue or illness, the ISFP's shadow may appear - a negative form of ENTJ. Example characteristics are:
being very critical and finding fault with almost everything
becoming bossy and ignoring others' feelings
having a very pessimistic view of the future
see hidden meanings that are not really there