Examples, immediately after FDR of media being biased? Ill give the span from Truman -Eisenhower.
NYT whitewashing of Stalin's USSR in the 1930s, for example. Of course they would blame it solely on Walter Duranty, but there were plenty of fellow travelers during the New Deal Era. Lincoln Steffans another example.
Probably many more examples out there. In the 20s and 30s it was cool to be Red.