The broadcast media stopped being the way a huge majority of people got their news starting in the 80s with cable. So the US returned to normalcy, with large portions of the population absolutely hating each other. The post civil war era was also abnormally amicable. Conservative Democrats found it easy to work with liberal Republicans and their constituents would still vote for them out of tribal/regional loyalties.

Hating the political opposition is the norm, not the exception.