The distinction between Hutus and Tutsis was exacerbated--all but created--under colonial administration:
Under colonial rule, first by the Germans and then by the Belgians, this hierarchical division was racialized and made more rigid. Ethnic identity cards were required, and the state discriminated in favor of Tutsi, who were considered to be closer to whites in the racial hierarchy. This was reinforced by versions of history portraying the Tutsi as a separate "Hamitic" people migrating into the region from the north and conquering the Bantu- speaking Hutu. In fact, current historical evidence is insufficent to confirm to what extent the distinction arose by migration and conquest or simply by social differentiation in response to internal economic and political developments.

In the post-colonial period, for extremists on both sides, the divide has come to be perceived as a racial division. Political conflicts and inequalities in the colonial period built on and reinforced stereotypes and separation. Successive traumatic conflicts in both Burundi and Rwanda entrenched them even further. Despite the efforts of many moderates and the existence of many extended families crossing the Hutu/Tutsi divide, extremist ideologies and fears are deadly forces. Far from being the product of ancient and immutable "tribal" distinctions, however, they are based above all in political rivalries and experiences of current generations.
[link|http://www.africaaction.org/bp/ethcen.htm|http://www.africaact...org/bp/ethcen.htm]

I'm not particularly sympathetic myself to the practice of "blam[ing one's] own shortcomings on the actions of people long since dead" (although some of them are still living--the Belgians didn't leave until 1962, and in the waning years of their administration they actively pursued an ethnic "divide and conquer" policy, which included the tacit support of some early massacres in 1959, in an attempt to fight the independence movement that had grown up among the previously favored Tutsis. Complicated place, the world), but in this instance it's tough to exonerate the colonialists completely--curious to think that the bland Belgians used to be such beastly brutes, and in living memory at that.

The roots of Africa's disadvantages vis-à-vis the rest of the world generally and their European and European-descended colonizers in particular, are discussed in some detail in Jared Diamond's Guns, Germs and Steel, and according to his thesis the causes long predate colonialism or, for that matter, industrial technology.

cordially,