Actually it's the opposite. Pre-internet, there were a handful of news sources in any given city (mostly newspapers and TV), so they couldn't afford to alienate half of their potential viewers/readers by leaning hard left or right.

Today, there are many, many sources of 'news' online. So many that the net effect is that most of those sources lean one way or the other, and by and large people choose to listen mostly or only to those sources they agree with.

No wonder political opinions are so highly divided today. Almost no one ever hears anything from the other side.