I don't understand what the focus of this ethnicity and culture DIR would be because some are already talking about race.
In most cases, there is zero relation between race and a particular religion, this is pretty much true for all the "major religions", they include and span all races.
As far as "culture" and race, cultures vary dramatically within a single "race", for example I interact directly with African nations such as Angola, Nigeria, or South Africa on almost a bi-weekly basis. Even considering race, I do not see them even all as the same race, the differences are as distinct between a Cabinda based African and North-Eastern Nigerian as are different as a Korean is different than a Han Chinese. They don't even look the same, even skin pigmentation is different. And their cultures vary dramatically, almost no resemblance, and within Angola there are four different cultures. I hear about "rap hiphop culture" in Oakland CA, many are "black" but that "culture" has nothing to do with "black Soweto culture".
In India, Panjabi culture is different from Tamil culture, so on and so forth. India has 24 official languages and vastly different cultures in the mix. What would you call the "India ethnicity and culture" sub DIR? "Asian"? What a joke - so members of my own family would use the same subforum as, oh, the Chinese?
hmmm... back to race, DNA research proves practically no one, zero, is any "pure race"... What race is my daughter? She has many races in her DNA.
Now if it is a new DIR where someone can talk about their regional (or diaspora) "culture", that might make sense. One dumping ground for all and no sub-sections such as "black" (what?) or "Asian", no.
So one place where ... oh, I don't know... someone can post something like "Hi, my name is Heidi! Here is some cultural info on my passion for German steins (stoneware Steingut) from my home near the German-Swiss border!" ... or someone posting about the culture of bread in their region of India, whatever ... but we sort of already have that now in various forums, yes?
I see a lot of "Euro" types in S.F. really into Anime Culture. They are "white", but Anime and Manga of Japan is their "culture". Where would they post to tell us about their culture? Asian? But the SF Anime "white" gals use different koolaid colors in their hair than in Japan, and they have a slight punk-goth fusion element with black lipstick and such.
eeeehhhh ... this isn't going to work, in fact it might start trouble already.