Apparently, they've never heard of Reynolds v. Sims
"Reynolds v. Sims, 377 U.S. 533 (1964) was a United States Supreme Court case that ruled that state legislature districts had to be roughly equal in population."
"Voters from Jefferson County, Alabama, home to the state's largest city of Birmingham, had challenged the apportionment of the Alabama Legislature. The Alabama Constitution provided that there be at least one representative per county and as many senatorial districts as there were senators. Ratio variances as great as 14 to 1 from one senatorial district to another existed in the Alabama Senate (i.e., the number of eligible voters voting for one senator was in one case 14 times the number of voters in another)."