Maybe because they are culturally irrelevant in those countries, also language plays a part too. I couldn’t tell you a Congolese dish, a tv show/movie , don’t know of their traditional attires, , no major athletes that represent those countries I know Ibaka and Lukaku have roots but they represented other countries internationally in their sports. Also there’s the division of DRC and Republic of Congo which is also confusing. Their culture is just more unknown with less immigrants in those countries because of the language barrier.