Obviously they are not commissioned, I never said they were. It is about respect for the duties and responsibility for the job that they do. That is all and I think it deserves the title of captain when in the work environment.
And I have found you an equally awesome wikipedia reference
First officer (aeronautics) - Wikipedia, the free encyclopedia
In commercial aviation, the first officer is the second pilot (sometimes referred to as the "co-pilot") of an aircraft. The first officer is second-in-command of the aircraft to the captain, who is the legal commander. In the event of incapacitation of the captain, the first officer will assume command of the aircraft.