The basis of the GPL license is the freedom for non-restricted use of the said software:
Nobody should be restricted by the software they use. There are four freedoms that every user should have:
- the freedom to use the software for any purpose,
- the freedom to change the software to suit your needs,
- the freedom to share the software with your friends and neighbors, and
- the freedom to share the changes you make.
Further details and the license text may be found here: http://www.gnu.org/licenses/gpl-3.0.html