Berliner's piece is full of obiter dicta--opinions stated largely without citing to support, and if Inskeep is correct, where support was adduced, it was done so in error.
I have heard interviews on NPR in the last few years with Mitch McConnell, Tom Cotton, Vivek Ramaswamy, Nikki Haley, Chris Christie, James Comer, and others of their party, as well as with Republican strategists and pundits. NPR's veteran Capitol Hill correspondent, Mara Liasson, is apparently a regular on Fox News.
I mostly (but not regularly) listen to Morning Edition with Inskeep, Marketplace with Kai Ryssdal, and Fresh Air with Terry Gross. Do you listen to NPR very often?
My impression from what I listen to is that most of NPR's product is not political. One of my favorite productions from NPR is Tiny Desk, a series that has featured hundreds of musicians playing at the NPR offices in a small setting. In the last year or so they've had many artists I've never heard of, along with Bono, Justin Timberlake, Indigo Girls, and Taylor Swift from the pop celebrity world (that I'd recognize, anyway), and Hilary Hahn, Alice Sara Ott, Yo-Yo-Ma, and Marc AndreĢ Hamelin from the classical side. Lots of jazz and blues, too.
Here's an example--Chick Corea and Gary Burton playing Corea's tune, "Crystal Silence."