From the Forum Rules and from the Registration Agreement:
Gaining unauthorized access to a private network, especially a state-supported university's network, is illegal and punishable both by the state and federal government as a cyber crime. Posting a thread and asking for assistance to commit a crime is a violation of forum rules and also involves interstate use of the internet, which falls into the jurisdiction of the FBI.
By your logic, this article is also against the law.
It describes how to gain access to open wireless networks, which is illegal.
But you see, the article is perfectly legal. What's illegal is actually gaining access to the network, not writing about how to get access to the network.
The original poster isn't breaking any laws by making the post, therefore the post is okay by the forum rules. What the poster does afterwards is beyond the jurisdiction of the forum.