In fact, that's pretty much what we're left with today isn't it; particularly "broadcast" journalism. Can you tie that in with the leftist agenda somehow? Or are they unrelated?
The partisan press took a vacation from 1865 to about 1960---but that's not to be confused with the "sensationalist" press, which never left. Now, PART of leftism is reporting the bad, namely the "progressive" notion that since the world isn't perfect, the status quo is always the enemy, so you must always report negative stuff. To from that perspective, sensationalism has always been leftist. I think the tendency toward "bad news" is progressive in nature; but when the bad news is accelerated and enhanced by partisan reporting, then it becomes the drive-by media.