Second OP's point is that yes, race is a social construct, with clear and consistent impacts in real people's lives every day. The census exists to measure things that may be used to inform policy.
Therefore, something such as race, even if it is an arbitrary social construct used to divide based on nothing more than skin color, is important to measure against other factors such as income and address. It helps you decide when/where/what is being discriminatory.
Race should be a weaker social construct, yes. But living in Infinite Fun Space doesn't help anyone today in the real.
As pointed out elsewhere in the comments on this thread, the census may have accidentally ended up enforcing white hegemony in America. See the anecdotes of people suppressing the reporting of partial indigenous or African heritage in order to pass as white. The data made America look far more white than it ever was. And despite the recent trend I doubt the effect has vanished. Are we so sure we want to be using that data for policy?
Therefore, something such as race, even if it is an arbitrary social construct used to divide based on nothing more than skin color, is important to measure against other factors such as income and address. It helps you decide when/where/what is being discriminatory.
Race should be a weaker social construct, yes. But living in Infinite Fun Space doesn't help anyone today in the real.