I care because they are promoting an image that is not true. And you as a woman (I am not) should care about it too. Because the picture means that only men, regardless their nationality, can be linux nerds. I would be offended if I were a girl who is a linux nerd. The same way they added 4 nationalities, they could have added a woman. Because they didn't choose 4 random guys and get 4 different nationalities by chance.