Why So harsh on UNIX for Personal Machines?

Unfortunately this policy must now be enforced. In the past members have been permitted to setup their own UNIX machines on the network without this restriction. Eventually some enterprising "hackers" (this is not really the correct term), used these machines to launch attacks on other networks. Many of these machines were used to relay spam email to other networks, most of which complained to abuse.net

In the interest in preserving the good name of the institute, this policy must be followed.

We realize that you may know what you are doing and will take proper precautions, however, we must apply the policy to all personal machines.