You know that those two sentences are synonymous, right? (Immigrant [in the United States] from East Africa, and emigrant [to the United States] from East Africa.) You and MisterBastahrd pointlessly chose to read it as "immigrant [in East Africa] from East Africa", or are trying to point out that most people haven't personally migrated, when that was clearly not the meaning of either my comment, or the one I replied to.
Also, it's emigrant, now that we've gone full grammar nazi.
As to its relevance, well the UN has other ideas. http://www.un.org/apps/news/story.asp?NewsID=23794