The media were radicalized in the early 20th century during the progressive era. This includes the Associated Press.
https://librivox.org/public-opinion-by-walter-lippmann/
https://en.wikipedia.org/wiki/The_American_Newspaper
The use of stereotypes to persuade readers(and later listeners and viewers)of a specific narrative while putting on a mask of “objectivity” was developed during this era.
Thanks for your great effort to document and expose the dangers of progressive spewing and their damage to America.