I would take issue with the idea that there were ever journalistic standards.
Since the beginning of printing, there have been political pamphleteers who slammed and denigrated any who disagreed with them. Jefferson and his Democratic-Republican (democrat party) friends secretly bought a paper to tear down the Washington administration even while Jefferson was Secretary of State. The Civil War era and the treatment of Lincoln by the press was as bad as it is today and yes, Lincoln’s GOP were against him and aided in the the smear. Nothing new, journalists have never had any ethical boundaries and never will; that concept is pure myth put forward by journalists.
Prostitutes have more integrity.
But what about the Walter Cronkite and Huntley and Brinkly years? Can we say that at that time Right and Left were not as far apart in their ideas as they are today. And perhaps that's why that era was viewed somewhat at the "golden age" of non-partisan press?