Certainly DRC has had terrible problems for many years, going back to Leopold's legacy. Congo-Brazzaville has certainly had issues, but far fewer than its neighbour. It was never a Belgian colony (nor a private colony of Leopold); it was always a French colony.
You are stating the obvious.
In terms of VFR traffic, I think the problems cut both ways. On the one hand, obviously the conflict (especially in DRC) limits traffic, but it also means that many people have emigrated from the country, so there are substantial Congolese communities in other countries who might want to visit their families. It's also worth noting that a lot of the traffic on these routes is aid workers, who are often willing to pay pretty high fares.
Ok clearly you seem to ignore a few things. Let me give you a few facts.
Kinshasa is a very large city, with a population estimated at 12 million people. Brazzaville's population is estimated to be around 2 million. Technically therefore, there should be more demand from FIH than from BZV.
However, few things hinder Kinshasa's traffic:
- DRC individuals do not have the right to have dual citizenship. This limits travel from congolese population abroad
- The difficulty of obtaining a visa for DRC generally speaking
- The economy is weak in DRC. Other than mining, banking and telecoms, there is not much happening. Mining centers are also not located in near Kinshasa. This limits business travel
- The poverty of people. (Gombe and Limete may be relatively well of, the rest isn't)
The rest of your statement is plainly misinformed: having flown several times both to FIH and BZV, and having lived in Kinshasa, I can tell you that aid-workers do not represent a sizeable proportion of people flying AF to FIH. What you see is VFR, and local and international business people. Also, DRC receives relatively little Aid in proportion to its population. Most aid flows to the East of the country (Kivus), not to Kinshasa. The kind of aid worker you imagine would be flying to Kivu via Kigali or straight to Goma.
Overall FIH sustains itself through the sheer number of people that live there. This creates a market, although, for a city of 12 million people, it's ridiculously small. SN seems to be doing better in FIH. More business ties. But even it performs triangular routes on soe days (via Luanda)