GNU in the computer software development community stands for GNU’s Not Unix (a recursive acronym — anyone familiar with computer algorithms understands recursive, or self-referential, self-calling procedures).
Unix is the famous computer operating system developed in academia during the early 1970s, for which the nearly universal Kernighan and Ritchie C programming language was invented, once it became obvious that the limitations of assembly languages (which are CPU instruction-set specific and provide no portability or programming structure) were found to be inadequate for the task. The C language was invented as essentially a portable assembler, which provided both low-level CPU access and high-level library capability.
GNU/Linux is an open-source operating system which emulates and mirrors Unix capabilities but with the source code freely distributable, available, challengeable, and modifiable by anyone who can figure out how to make it better.
It thus seems to me that applying the GNU concept to the “new” atheists is totally inappropriate and self-contradictory, since they want to keep their “source code” (Darwinian orthodoxy) private, unchallengeable, and un-modifiable by anyone who might be able to figure out how to make it better.