Arriving across the border [from Rwanda in 1994] in Goma, in what is now Congo, McCain found cholera victims stacked beside the road "like highway barriers." "I remember having to step over the decomposing body of an infant, covered with white powder, lime I guess, to get into one building." The field hospital covered four acres. McCain's team provided primary care for sick and frightened refugees, many of them suffering from dehydration. For nearly a month, McCain organized deliveries of food and water for the operation, collecting supplies at the Goma airport.
Still not an explanation why the body was not moved, but when there's that much death (and that many bodies), I imagine that one becomes hardened to the sight of it and saves one's respect for the living. Also, when one is visiting in another country, I'd think it would be presumptuous to assume that another culture would have the same ideas/beliefs about "respecting the dead" that one holds in one's own country.