"Africa" vs. "Middle East and Africa"
The thing to note is that both topics include "Africa".
What goes where and why?
This isn't a purely academic question. Notice that both boards
contain questions and reports about Morocco, Tunisia, Egypt.
It seems that Africa is mostly non-North African posts with a smattering of N. Africa. While the Middle East and Africa is either all N. Africa or Middle Eastern Countries / Gulf State's rec's and no southern Africa posts.
So while you could post North African rec's on either board the Middle East and Africa seems the better bet. But it looks like you would be okay on either board for those particular countries.