This article paints a picture of poor, helpless employees who depend on other people for far too much.

Two quick points:

First, the assertion that “These employees have no other way to find each other but through work email” is demonstrably false.

There are a many other ways for people to communicate outside of email systems owned by others.

If those employees are incapable of accessing any of the myriad free alternatives to company-owned email systems, then they have far worse problems to deal with, like incompetence and helplessness.

Second, the use of a company’s email system is a privilege, not a right. The owners of those systems have every right to determine what is appropriate and it makes perfect sense for them not to allow communications that may interfere with the company’s operations, management, or productivity.