The "3rd world" is huge. Anyone who thinks otherwise is clearly in need of a less-misleading map.
On a traditional Mercator projection Africa looks to be smaller than the United States and Canada combined. In reality Africa is 50% larger - and those are the 2nd-largest and 3rd-largest countries in the world!
Obviously. Every projection will be off. Unless you are a 15th-century sailor, there is no reason to favor the Mercator projection over any other one. Sticking with it is also a political choice.