Most state motor vehicle departments will issue a photo ID to NON drivers. That would seem to be a solution for this irate "traveler".
The problem this traveler has is not showing id, It is just he simply wanted to see the law requiring him to do so. Apparently mere citizens are unable to see this specific law, If after an open debate in Congress it is the law that we must have Passports to travel in this country, say border stations at State, County or City lines, then so be it. Think of all the bad people we could catch, and if you did not break any laws (hopefully you wouldn't break any secrete ones) you would have nothing to worry about.
All states will issue non-driver ID. How do you think the homeless get their booze? They don't drive.