The point of adding the question is to undercount non-citizens. Legal residents will also be undercounted. Legal residents aren't cheating. We should just ask Facebook how many people live where and save ourselves the trouble of this archaic data gathering.
I believe you are confused as to the purpose of the Census.
The Census determines the population of
constituents (
being a voting member of a community or organization and having the power to appoint or elect) in each state in order to apportion representation in the House of Representatives. That number is fluid, and is based on each states' percentage of the population as a whole. That percentage determines how many of the 435 Representatives each state has.
Natural and naturalized citizens are the constituents of our representatives in Congress. Non-citizens have no voting rights, and by default, no right to said representation.
This threatens the very core and foundation of the Liberal Movement. THAT is why the wailing and gnashing of their teeth is deafening.