Gerrymandering is also bipartisan, because it makes things safe for terrible Republicans and Democrats alike. New Jersey Democrats tried to abuse the state constitution to rig themselves guaranteed supermajorities for the foreseeable future, and only backed off thanks to a national outcry. One of the most gerrymandered states is Illinois, which packs districts in the Chicago area so they're safe for Democrats while making downstate districts locks for Republicans. 90 percent of Illinois races were either uncontested or only had a token opponent. That's also how an avowed neo-Nazi could get on the ballot. If your rules are terrible, you attract terrible people.
Laws that make it harder to vote, or rig the elections that you can vote in, favor incumbents. So any dirty politician -- like the one who stayed on the ballot and won while on trial for shooting his wife -- has a lot to lose if voting becomes fairer. Yes, Southern voting is a mess that needs to be addressed. But ultimately, it doesn't matter if a politician is a Democrat or a Republican if, first and foremost, they're also a colossal shithead.