Because in the US, at least in my experience, 'starving people in africa' is kind of a colloquial trope - it is more readily referenced than starving people in asia, since we don't see charity organizations constantly using asian faces to advertise their foundations.

>forced into producing cash crops for export to Western Europe

Who exactly went around the the countries in africa and asia and disallowed them from growing their own food instead of cash crops? My bet is that these places found economic incentive in growing these crops rather than what they would consume locally - whether the global economy is a net benefit or net loss for a poor country is an entirely different discussion