The dangerous parts to me are three fold
1.) People only want to listen to things that confirm their beliefs, and instantly discredit anything that doesn't.
2.) The nationalization of both parties, really starting with Newts Deal with America, has led to homogeneous candidates. It's hard not to support straight party when everyone in a party looks the same. A Democrat won a special election here recently, and liberals lamented he wasn't a "real" liberal because he supported gas drilling and was pro life. But he was also very pro union and anti Trump tax cuts. To me, that's a good thing. Not his positions necessarily, but that he looked what like a rust belt Democrat should look like. Why should a rural Western PA Dem look like an NYC or Cali Dem? Likewise shouldn't an NYC Republican be more of a libertarian than an Alabama Repiblican? If candidates within parties differed we could find common ground across the aisle. Since they don't, it's almost impossible, because the parties are universally opposed on every issue.
3.) Most "news" is just opinion now. So instead of taking in the news and formulating one's own opinions, people simply pick the pundits they tend to agree with and just regurgitate their opinions.
