did The Future release the source code for WM EX?
Not to my knowledge.
Isn't the point of the GPL to prevent this situation? Check out the gpl.txt in the main WM (or WM-EX) directory:
Therefore, you have
certain responsibilities if you distribute copies of the software, or if
you modify it: responsibilities to respect the freedom of others.
For example, if you distribute copies of such a program, whether
gratis or for a fee, you must pass on to the recipients the same
freedoms that you received. You must make sure that they, too, receive
or can get the source code. And you must show them these terms so they
know their rights.
In other words, anyone can fork a project, but
no-one has a right to make a fork closed-source. I'm sure we all prefer a closed-source WM-EX to nothing at all, but we do have a right to the source, and to make our own sub-forks. (Unless, of course, there is some dual-licensing going on; but since WM-EX comes with the GPL text intact...)