I noticed it when I was a S/O and then a F/O ... I thought those voicing it stupid and ignorant of the realities of airline aviation. Sometimes when I was a F/O an agent/passenger would approach me for a "Captain's call" about something or other ... I always pointed at the Captain and said ... "why don't you talk to the Captain , I'm only the First Officer"???
"That ain't my department, sir."