And this is nothing new...not at all. Look back through "journalism" from the Civil War. The partisan press (for all sides, not just one) has been a fixture in the United States for as long as we've been a nation (and most likely before that, even). There have always (or usually) been a few more "intellectual" outlets, but they had very limited distribution compared to the staple broadsheets of the times.
This is very true, but I'd argue that this was not always well to the good. We tend to forget given the relative domestic peace of the past thirty years just how remarkably violent the U.S. was during the 1800s, the glory years of ferociously partisan (and often party-run) news sources. The rise of the Democratic Party under Jackson and Van Buren, for instance, saw genuine political mobilization towards the illegal expulsion of the Cherokees, for instance, led by Democratic newspapers. And then, of course, there was the Civil War itself, the ultimate factionalization of the country.

So yes, I think an aggressively partisan media is absolutely bad for the country. I'm not that old, but I do remember when CNN Headline News, for instance, actually reported just headline news.