East Africa doesn't have many neighboring countries, and Belgian Congo is one of the friendlier ones. After all, Belgium is just a small country in front of East Africa, and its strength in its African colonies is very weak. The countries even have a bit of a family relationship.
In fact, Portugal and the Heixinggen royal family can also be considered relatives, though it requires tracing back two generations, related to the grandfather's uncle. After the death of the former queen of Portugal, there was basically no further contact, which is also why East Africa was unrelenting towards Portugal.
If a conflict were to arise between East Africa and Belgium, they would certainly negotiate first, especially since King Leopold II of Belgium is Karina's grandfather, bringing them much closer.
In 1885, Belgium was also a colonial "winner"; taking advantage of the Berlin Conference, it solidified its colonial legitimacy in Belgian Congo, which was recognized by various countries.
