The Arab, Indian and Filipino subforums exist because the site owner felt these small niches needed a special spot of their own. And I suspect felt they may attract more users from those areas.
It seems to have not worked as those are three of the least used forums on the site, and at least half those that do post in them neither live in those regions or seem to even be of the particular heritage.
Don't hold your breath on seeing an expansion of other countries added to the list.