I take issue with the idea that diversity is about things like skin color and gender. Even if a group is all of the same race, gender, language, income and nationality, they can still be incredibly diverse when it comes to their views and experiences related to free software.
If we wanted to encourage diversity in the free software space, we should make sure every type of free software user feels welcome. Not just Linux users, but also BSD users, as well as folks who use Windows or MacOS but enjoy free software like Blender.
Of course, free software naturally has a greater appeal to tech-savvy computer users and software developers, which is a group that is overrepresented by Americans, English speakers, men and white people, mostly due to economic reasons. But these characteristics have nothing to do with free software, and there is already a diverse range of viewpoints and user profiles within the free software space.