C.E. Evans wrote:
Actually, it is. It doesn't have to be literally termed as commissioned and noncommissioned, but there is indeed a distinction between those who do "grunt work" and those with administrative duties. And as with police departments, it could be easily be a case that all Starfleet personnel could be referred to commonly as officers regardless of their actual rank or duties.
No, it is clear that not everyone in Starfleet is considered an "officer" the way members of a police department are. In "The Drumhead" Picard asks Crewman Tarses whether he ever considered going the Academy "to become an officer." That line would make no sense if all Starfleet personnel were "officers," since Tarses is clearly serving in Starfleet at the time.