…waxed nostalgic for a time when friendships and romances blossomed across the aisle

Of course they did. And there were friendships across the aisle. But this was before the ‘great sort’. Parties each used to encompass a wider range of individual politics. Then Barry Goldwater decided to ‘hunt where the ducks are’, and looked to pull Southern Democrats (the ‘Jim Crow’ wing) into the Republican party. Those Dixiecrats were moving away from the Democratic party over civil rights (LBJ). At the same time, Blacks were moving away from the Republican party (LBJ / civil rights, again).

We’re all pretty siloed now — and like most everything else messed up in this country, it comes down to our ‘original sin’ of Black slavery — and the invention of ‘race’ to justify it.