Technically he said that death and starving in Africa are caused by development, not "all problems", but you're right, I should have read the criticism section more closely; my bad. Although I think his comment is a little more nuanced than you made it seem, and I partially agree with him about the destruction (at times intentional) of nature-based cultures, you are correct in pointing out the silliness of some people in pointing to outside factors as the sole cause of Africa's problems. The disappearance of "development" from Africa would not solve the problems, but I think he hits on something by implying a connection between the removal of self-sufficient lifeways and starvation.
Thank you for a civil response.