It's pretty ironic that an article that decries the rise of polarization, using the term "polarization" 18 separate times, ends up being basically just a checklist of one-sided ideological complaints about the other side.
polarization noun [1] : division into two sharply distinct opposites especially : a state in which the opinions, beliefs, or interests of a group or society no longer range along a continuum but become concentrated at opposing extremes political polarization … the relationship between partisan polarization and legislative gridlock is direct, with stalemate more frequent as the political center shrinks. — Sarah A. Binder The drift in our society now is not toward a grouping around the middle, but toward polarization. — Richard Todd … the venue where our most fractious … arguments over identity occur: the internet. These arguments do not play out on a democratized playing field where all identities are weighted equally; rather, they play out in a meticulously crafted environment where identities are microtargeted and polarization is amplified by algorithms. — Emma Levy
It seems that if you're talking about polarization, the word is going to come up more than once.
Their position seems to be that polarization (in the sense of the sides being pushed to extremes) is a bad thing, they claim that has happened, and yet they are extremely one-sided.