But apparently at least a few states outlaw gerrymandering and the practice can be challenged in court if you can prove they were drawn unfairly for the explicit purpose of giving one party an advantage. It's notoriously hard to prove that and these people are hoping they've created tools that be convincing to a judge.
Of course, not all partisan advantages are the result of gerrymandering. State boundaries aren't gerrymandered, but equal representation in the Senate still results in extremely disproportionate influence of rural people.