This argument seems like grasping me to. How would one function in society at all without an ID? Opening a bank account, cashing a check, driving a car, visiting a doctor, taking a train or plane, going to court. These are all activities which require ID. Sure, there is a tiny fraction of people who can't engage in those activities. But how likely is it that those folks are going to be voting, anyhow?
I found this video pretty funny while searching around: https://www.youtube.com/watch?v=rrBxZGWCdgs