Bloom and Sachs (1998) paper and Angola’s loss of Economic Diversification

Came across a paper by Bloom and Sachs (1998), after having had the pleasure to see Sachs delivering a talk on former US Pres. Kennedy at LSE Ideas last Monday 15 July.
Well, I needed to read the paper as part of me setting up my literature review for my current research project on economic diversification in Angola. But, what caught my attention, and made me write about that, was not really anything more than the fact that researchers are often trying to explain why Africa (particularly its sub-Saharan part) is by all means (and measures) always lagging behind (with particular emphasis to economic development).
I really found their arguments interesting while at the same time annoying. They argue that geography seems to "conspire" against Africans making them less productive and prone to all sorts of malaise. Sure, they (as usual) provide all sort of evidence to support this main idea.
Some days ago, I read a book edited by Oya and Santamaria (2007) and found an interesting and curious observation that Oya makes on Bloom and Sachs (1998) paper, which he built from H-J Chang, that maybe (to escape this "geography curse") African countries should military invade those countries far from the tropics and eventually change their fate! This was just one more example of how Africa (and Africans) seem to be very often misrepresented, and how its problems tend to be looked at, by some researchers, without taking into account historical processes.
As I progress with my research on Angola, I see a country whose economy used to be diversified (I was surprised to find out that Angola was once the 4th world producer of coffee! So we had to have some agricultural knowledge and expertise to be there), oil was only found around the 50s and it was mainly during the war followed the independence from Portugal in 1975 that it took the prominence it has today. Would anyone call that "Dutch disease" or "resources curse" effect? I wonder how one would expect people to farm while bullets are being shot at them and when young people were being dragged to the front lines to fight, instead of being given chance to be educated and farm the land.