FDR was furious. He wanted the Chicago Tribune editors and reporters jailed for treason. He ordered the US Attorney General to arrest them. But at the time, the Allies were about to break the Nazi cypher machine code (Enigma). FDR was advised not to pursue prosecuting the Chicago Tribune because the publicity of a trail may cause the Nazis to change their codes. So FDR dropped the matter.
Ther is no such tactical consideration here. THe question is did he or did he not break the imbed rule?
Your story shows that FDR dropped it because of practical wartime reasons not political considerations. If the government won't police the press there will come a day when the people will.