Since the GNU project is a software project, it has no gender to speak of (it neither lacks one, or has one). So there is little point trying to define it as some specific gender. And by virtue of being a free software project, it cannot exclude anyone.
Trying to reach out to more groups is probobly better suited for organizations like the FSF. I think why the GNU Kindness Guidelines concentrate on how to be kind, instead of specifying what is unkind is that the former is far more positive, and happier to read than the later.
