Lack of contraception is not causing the deaths in Africa, drought leading to famine is. There will always be droughts on that continent, and thanks to climate change they will probably happen ever more regularly. People die because impoverished countries dont have the infrastructure in place to deal with severe climactic events even although they are predicatable.
A deluge of condoms and a highly unlikely cultural shift, might thoeretically reduce the birth rate and lower the population, however, come the next big drought, that existing and reduced population will still be subjected to the suffering we have witnessed.
In 50 years time, this mythically contracepted reduced population, will also be an ageing population, an aging population with few offspring to help them when the next famine hits. People will still suffer and die, lots of old and sick will die, and yes , many of the reduced number of children will die. Thats what happens in droughts/famines, people starve,whatever the population size.
Droughts will always happen and without provision of infrastructure to deal with water shortage people will die.
You mention the success of the antipromiscuity message in the fight against AIDS in places like Uganda. Strange then that in your OP you seem prepared lay the entire blame for Africas problems at the feet of the Catholic church, who have promoted monogamy ad nauseam. You do seem to be contradicting your own points. Whatever you think of the RCs or the other faith organisations, they are infact there, decade in , decade out, raising money and doing what they can on the ground. You rather ingnorant of the importance of the work these organisations do, they ARE still there when live aid and the big appeals have faded from memory, they just arent very glamorous.
Indeed, they havent made huge changes to the conditions out there, but I shudder to imagine what it would be like if they werent there on the front line. Only govenments can achieve the massive changes you talk about by adressing corruption, debt payments to western banks, war, and all the other issues which mean that there is nothing being spent on making these countries "drought proof" or at least "drought survivable"
Condoms are irrelevant.