The Dems are gaming the system. Referendums are perfect for issues that sound good at first glance, but have terrible unintended consequences. (unintended by voters, but intended by the Dems)
When progressives passed the 17th Amendment, giving the people the right to directly elect the Senate, it sounded like a great idea. Democracy! Yay! Except that it undermined a very carefully constructed system of federalism designed to keep our national government from usurping power intended to be held by the states. That was probably the primary goal of the progressives...not to increase democracy, but to centralize power in DC. But the people didn't vote to centralize power in DC; they voted to increase democracy.
These "anti" gerrymandering provisions are just like that. They replace one kind of gerrymandering (one controlled by the people) with another kind of gerrymandering, which will supposedly be controlled by an unbiased group of people. Except that such people don't actually exist, and they are really just replacing it with a group of unaccountable people. The voters voted for impartiality, and they got unaccountability. And, they also got a concentrated group of people, which makes it easier to corrupt the process.