Following up on this post, Brett Bellmore writes via e-email:

I’ve now had a chance to read the ruling, and it does not appear to be based on the judge’s belief that ID fraud is a more serious problem than absentee ballot fraud, but instead his (I think quite reasonable) belief that the whole question of which is more serious is utterly irrelevant, since the legislature is perfectly entitled as a constitutional matter to address small problems, and leave big problems untouched.
I tend to agree that absentee ballot fraud is the bigger problem. On the other hand, that also means that it has more defenders, and going after it will be a bigger fight. Maybe voter ID will be a good warmup for that battle royal.
Brett Bellmore

I still have not had a chance to read the ruling in any more detail, but I do think some of it may be a function of the judge’s belief that the Democratic lawyers did not present enough evidence to support the arguments they made in their brief. I wonder if more evidence would have mattered here.