Dave, you're right. I lived in Ghana for 10 years in the '70s/'80s and we always took Salt Tablets with us when we went travelling. Put them in puddles when we needed them.
The thing about Oxfam is that these countries are rich - look at Zambia, used to be 'the bread basket of Africa.' Africa could be more wealthy than the west, but you can throw as much money as you like at it, the money ends up with the bureaucrats, (most at a low education level), and the poor get poorer. Oxfam will not address this and, indeed, have their own rich bureaucrats.
How similar is that here today?