This is a joke, isn't it?
1) It's a racing style bike. I haven't been to Africa yet, but could it be that the streets are not of the best quality? A racing bike needs streets with a good roadbed. So I think a trail or mountainbike style would be the more appropriate one.
2) Only the frame is made of bamboo. There are enough other constructive parts that have to be manufactured with steal parts.
3) Why does a bike for poorer countries need disc brakes?
As you quoted the Bamboo Bike Project's website: »[...] bicycles currently used in Africa are utterly inappropriate for transportation in these regions.«
I think this can also be applied on the Bamboo Bike Project: neither it reflects on the environment where it is used nor does it (except the frame) cater to sustainability.
It is a mere style product with an additional USP being sustainable and helping people in Africa... bullshit if you ask me.