This is an issue that our folk moral intuitions can get horribly wrong. It's a lot easier to think "people in Africa are suffering, so it's morally right to help them" than to ask "is X actually going to help them?"

This is true, but in this case what is going wrong is our intuitions about instrumental values, not moral ones. I think thomblake was talking about whether our folk moral intuitions could determine whether it was a good or bad thing if we did something that resulted in less suffering in Africa. Our intuitions about how to effectively accomplish that goal are a whole different beast.