Oh but there is. The govt (meaning liberals)see people always as members of some group-- ethnic group, racial group, economic group, cultural group and whatever else...and then decide what victim status to assign to that group. Once a victim status has been assigned, it comes up with programs to help that group move ahead and overcome all barriers placed before it by an unjust society. But programs require money, and people, to administer. Thus new taxes are introduced, existing ones raised, more people hired and new govt agencies and depts formed. Getting your racial information is about helping you.
Black + White = Black.
In fact
Black + X = Black,
My guess is among other reasons, this convention has been defined by liberals as it adds to their constituent base. If you are non white, you are automatically a Democrat. Racism is so deeply rooted in liberalism, just that its not immediately obvious.