"Audience" is not the same as "content" or "viewpoint" or "bias," now is it?
You posted the article. I quoted it. The audience changed because the content changed.
'It’s true NPR has always had a liberal bent, but during most of my tenure here, an open-minded, curious culture prevailed. We were nerdy, but not knee-jerk, activist, or scolding.
In recent years, however, that has changed. Today, those who listen to NPR or read its coverage online find something different: the distilled worldview of a very small segment of the U.S. population.
If you are conservative, you will read this and say, duh, it’s always been this way.
But it hasn’t."