I have to ask: what purpose do these community pages serve?
Communities are a fundamental component of Second Life, yes. But that begs the question: what is a community? I would argue that for something to be understood to be a 'community', there needs to be more than just a trait that anyone can spot. Its members need to self-identify as part of the group, and intentionally come together because of shared experiences.
Taking the "Black Culture in Second Life" page as an example: that is a demographic, not a community, and a poorly defined one at that. Reading the page, it becomes abundantly clear that it is not so much a celebration of 'Black Culture' but of the experiences of the African Diaspora in particular as seen through a very American lens, lumping in foreign demographics who may or may not identify with it and who were probably never asked in the first place. Yikes.
As others have noted, the question of which communities is very prominent. Second Life thrives on selfmade, self-regulating communities. That is what needs highlighting more than anything. But SL's community tools are archaic, and while trying to move beyond highlighting 'destinations' is a good idea in principle, highlighting communities is and will remain a problem up until the point that community tools such as groups get a complete overhaul to act as "community profile pages". Do that, Linden Lab, and you will have an endless amount of communities to promote.