Why the GPL License for PC-BSD Installer?
All custom software developed for PC-BSD, The GUI Installer, Package Manager, Package Creator, were developed using the QT libraries. (www.trolltech.com) QT is one of the most powerful, solid C++ library sets available today, but it does not allow releasing under the BSD license, only under the GPL, or their own custom license QPL. For this reason, we have chosen to go the GPL approach. This was not intended to *pollute* the BSD license, just as a user running KDE on BSD doesn't intend to pollute the license either.
So they had to either write a GTK installer (and using KDE as the desktop, this wouldn't make sense), pay Trolltech for a QT license, or release under QT with the GPL.