So what are the sides of our current “serious” discourse?
What do you think should constitute ''serious'' discourse?
I think serious discourse is based on the concepts in logic of soundness and validity: internally consistent arguments, and arguments that are externally consistent with a generally agreed upon body of facts.
I do not agree with any notion that there are no objective facts.
After that, I think all valid and sound positions should be considered when formulating policy.
I think that Republicans and lobbyists affiliated with Republican Party positions (wealthy elites who want to pay as close to $0 in taxes as possible, global warming deniers...) recognized years ago that not only is there no penalty to not adhering to these standards of serious discourse, but that lobbying by lying to the public was the most effective way to get favored policy enacted.
Lying to the public through propaganda or other such techniques is as old as mass communications, but in modern times, I think it was the tobacco lobby that first honed these techniques about 60 years ago, and they forestalled all but the initial actions for about 20 years.
https://edition.cnn.com/2009/POLITICS/06/19/tobacco.decline/
