I am not saying it should be done or anything like that. I would prefer the peaceful way of imposing sanctions on a country like that until they complie. Also they have had thousands of years to do something and they never really advanced much.
That's because of European colonialism in that area. In the past, the Europeans would come over, conquer them, and steal the resources in their land. They would encourage meaningless tribal violence simply because it made them easy to control. They made damn sure that the next generations grew up stupid and ignorant, because taht made them easier to control. And the Africans do revolt. Many African countries are one big story of one revolution after the next.

What do you define as just? Protecting Europe from being overrun by a fascist dictator who would have purged every country he commanded, of racial minorities and those he did not consider to be part of his perfect race, persecuting and premeditating the genocide of millions of Jewish people across Europe. Was it "unjust" of the British government to fight for the freedom of their country? Was it morally wrong to oppose a man hell bent on the genocide of one race? Hell no.
But again, to say that war was waged for jsut purposes would be a lie. Was it jsut for Hitler to do what he did? Of course not. I agree it was just for the countries to defend themselves, but it was not just for Hitler to roll his tanks anywhere he pleased. A war will never be started for any other reason than for power, greed, anger, or hatred. Period.