"Since the initial release of its source code in 1991, it has grown from a small number of C files under a license prohibiting commercial distribution to its state in 2009 of over 370 megabytes of source under the GNU General Public License."
OK, technically correct, but access to source code and a restriction on commercial distribution is not what people usually associate with propietary software. When you say propietary what most of us think is Linus releasing binary-only versions of Linux in 1991, which is false. I think "almost free software" is a much more accurate description, and a lot less flamey.
And by the way, the GPL was first written in 1989, so you could hardly argue that in 1991 many people understood how free software should work or which are the longterm consequences of using a certain license for your hobby project. Cut Linus some slack, he released source code and eventually used the GPL, right?
