It actually exists in a lot of circumstances and almost always disenfranchises the poor. Voting is a right, not a privilege (like driving, for example). Because voting is considered a “right” then any laws that mandate voter ID need to ensure that getting that ID doesn’t place an undue burden on citizens, and it must be free otherwise it could be considered a poll tax.
Not everyone lives the way many of us on this board do. Many people don’t have cars and must take mass transit, so any voter ID places would need to be easily accessible via mass transit. They would also need to be open extended hours to accommodate those who can’t afford to take even one day off of work to stand in line for a voter ID. The elderly are particularly negatively affected by voter ID as they often are immobile.
I too am not against voter ID, but it has to be easy to obtain, free, and not place an undue burden on anyone.