Also, I meant to follow up and point out that we don't have issues with people doing this on a large enough scale to warrant more stringent requirements. There is no reason to make it harder to vote, and it would make it harder to vote for sure. As for racist: it has been demonstrated many times that government facilities exist in a far smaller number in minority dominated area.
Also, how would you even show an id to mail in a ballot? That part doesn't even make sense.
Voter ID is a fundamentally bad idea, and I used to ask the same question, I've just realized why I was wrong.