New Georgia voting law: I dont get it... why would  Dems be upset voters must show ID?

Because the voices in your head say so 

The big problem with these laws is that they can keep waffle voters from casting a ballot. This may seem crazy to those of us who have a driver's license since we can't imagine living life without it. But if you don't need a driver's license, or haven't been able to get one, having inappropriate ID might be more difficult. It doesn't help that many of these laws are administered in ways which make it clear that they are about voter suppression. For example, in North Carolina, the Republicans who framed the state's voter ID law actually sought out information on what forms of ID were popular among African Americans and excluded many of them for qualifying under the law. In Alabama, the state was planning to close down every DMV office in nine out of the ten counties with the highest number of African Americans. These laws run the risk of keeping people from casting a legitimate ballot. The numbers aren't trivial. At one point Florida it was estimated that perhaps one in ten African American adults lacked a ID which satisfied the law.

This might be acceptable if there was some sort of big problem which it was solving, but there's not. These laws are often framed as an issue of voter Integrity. But the only form of fraud protect against is voter impersonation, where someone actually physically goes into a polling place and pretends to be someone else. But that form of fraud is so rare as to be essentially nonexistent. One study, conducted by a pro voter ID law organization found only about 200 credible accusations of voter impersonation in an almost 80 year time span. During that same time there were billions of ballots cast. Statistically, you are much more likely to be struck by lightning while going to vote and you are to find that someone has voted fraudulently in your name. Given the extreme low likelihood of voter fraud of this sort happening and the fact that these laws could potentially keep thousands of registered voters from casting a ballot, it's probably a good idea to opposed them

Except there's no evidence that undocumented immigrants vote nor is there any that states that voter ID makes elections any more secure.

Look, given that there is no evidence of any voter fraud at all the ONLY purpose of these voter ID laws is voter suppression.