clause 3 of GPL v3 - possible conflict with DFSG

[Shriramana Sharma <samjnaa@gmail.com>]

Please can anyone translate clause 3 of the GPL v3 to plain English?

Am I wrong in understanding that it means that no-one may use a software 
licensed under GPL v3 to enforce DRM? If I am not wrong, then does not 
this conflict with clause 6 of the DFSG - "The license must not restrict 
anyone from making use of the program in a specific field of endeavor." 
thereby making GPL v3 non DFSG-free?

Shriramana Sharma.