I think some of it is a general hubris common to all primates, and some is a conviction that what they believe is the linchpin of our Democracy, and now, that the other side is controlled by its extremes (I’ve been guilty of this).
Rapid societal change always contains real danger, and the young have always embraced whatever siren song is the moment’s rebellion. Honestly- is some tranny’s demand of a special pronoun really “the civil rights issue of our time?”
The older folk fear change because, as Tacitus said- “Experience Teaches,” and while the decades can mellow a person, they also contain enough examples of upheaval’s human suffering to make them fear it. It is worth remembering that many of the traditions recast as racist, etc. were cherished foundations of our morality as a people. This, by the way, does not include actual racism, and so the accusation is the more offensive.
In both instances people are afraid to give even an inch in fear the other side will take a mile. The most bitter irony of this is that if the partisanship disappeared tomorrow we would find the people on the other side to be just like us.