Thomas joined the liberals here because he doesn't like black majority districts.
Good. Nice to see him consistently apply his beliefs without regard to whether or not the party that nominated him benefits.
Thomas seems to be somewhat more consistent in that way than someone like Scalia ever was (example:
Ashcroft v. Raich, where Scalia seems to have decided in the opposite way that you would expect because the issue had to do with marijuana rather than something else). So while I certainly disagree with Thomas on almost everything, I can respect him for that.