Apparently, there are developers who release their source code under the GPL without understanding what it says. Or did I misunderstand the author?
For example:
ExcelPackage is an Open Source project provided under the
GNU General Public License (GPL) as published by the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
The GNU General Public License can be viewed at http://www.opensource.org/licenses/gpl-license.php
If you unfamiliar with this license or have questions about it, here is an http://www.gnu.org/licenses/gpl-faq.html.
The code for this project may be used and redistributed by any means PROVIDING it is not sold for profit without the author's written consent, and providing that this notice and the author's name and all copyright notices remain intact.
Emphasis was mine.