So, you think that if you swapped R and D in the dataset, then the algorithm would always make the D win? Given that they are talking about open source tools, that should be trivial for someone to prove, if they were so inclined.

It sounds to me like you just don't like the possibility that "your side" might be doing something politically nefarious. And don't get me wrong, it's likely that both sides are gerrymandering. It just so happens that republicans have more governorships and other state power, and have had much more opportunity to draw districts.

You should be happy about the existence of mathematical tools to try to prove when someone in power is choosing their voters, instead of the voters choosing the person in power.