This article could have been published 30 years ago. In professional unix admin circles this was already well known back them. Although I could be misreading it as the article is not very clear. I think this are the points it is trying to make:
1. Once upon a time you could rely on the passwd file and shell behavior as an effective means of authentication and access control.
2. It has been a very long time since that was an effective approach, for a variety of reasons, and you should not do this on modern production systems.
1. Once upon a time you could rely on the passwd file and shell behavior as an effective means of authentication and access control.
2. It has been a very long time since that was an effective approach, for a variety of reasons, and you should not do this on modern production systems.