If only White, how does the race change when one moves to another continent? And if White Hispanic, why not have also "Italic" or "Scandinavic" or "Arabic" or whatever other peninsula-ic races?

Because we don't have as much useful sociological data on this. Obviously we can start collecting data on any of the proposed categories, but if we're the only ones, it won't much help us figure out how LW differs from what one might expect of a group that fits its demographic profile.

Since I believe the question was intended to determine the cultural background of LW readers, I am surprised that there was no question about country of origin, which would be more informative. There is certainly greater cultural difference between e.g. Turks (White, non-Hispanic I suppose) and White non-Hispanic Americans than between the latter and their Hispanic compatriots.

Much of the difference in the example of Turks is captured by the Muslim family background question.