Hello David,
This particular week's feature was put together slightly differently in order to act on Mr. King's recent death. These weekly features serve purposes beyond fun exercises for WikiTreers, and those other purposes help keep WikiTree free for everyone, thus it is important to act on current events when we can.
In setting up this one, the Team looked for non-Americans to feature, but all those that were in categories or on lists from internet searches were not connected. If you'd like to see more non-Americans, make sure your favorite Notables are connected and have nice profiles, as well as appropriate categories so they can be found. Participate in planning discussions, too.
There is a lot that goes into each week's choices. As an American company, we'll never get away from US-specific features, but we do try to make sure to include as many other countries and ethnicities as we can and are appropriate.