No, I’m making a completely different argument. The point is that Georgia Democrats are closer to Georgia Republicans than California Democrats are to Georgia Republicans. When politics is locally focused, there is less acrimony because the sides are less far apart.
But when Georgia politics came under the national spotlight, it became a proxy for the fight between New York and California Democrats and Mississippi Republicans. “Democrat” in Georgia used to mean Zell Miller, but now refers to Nancy Pelosi. That greatly increased the acrimony of politics in the state.
Your point about Biden actually supports my point. Before southern Democrats rescued his campaign, the Act Blue donors and activists were running a carnival where candidates were all raising their hand to open borders. Trump didn’t run against Biden, he ran against those people. That’s only possible because New York and California Democrats have so much power over the party apparatus and messaging that it’s easy to make them the face of the party.
If the states were split up, that wouldn’t happen. My county exec is a Democrat, but it’s hard for me to get worked up about him because he’s a farmer. If folks in New York and California had no input into the laws that applied to me, or how my schools are run, etc., I don’t think I would follow politics at all.