Politics is a game of 4 corners in which everyone retreats to their own political corner and attempts to avoid being called out. Partisans tend to socialize with those with similar political views. Individuals consume news media which conforms to their prior beliefs. This is not necessarily to avoid opposing viewpoints but because they find conforming opinions more credible. Social media can change political minds, but instead tends to be a giant echo chamber which widens gaps between groups. Thereby increasing ideological conformity and political polarization is self-reinforcing.
Now, who’s “it”?