Most third world countries have low percent of IE users (almost always lower than the mean, generally much lower), it's not a strange phenomenon. IE usage works as a (very coarse) estimator to percent of the population with regular Internet access. Try it yourself.

I personally think it happens because in those countries, in order to have access to technology you need to be from the upper socioeconomic class. Usually those users have a higher level of understanding about technology and hence choose to customize their browser.