again, did you ever watch the show? Some bureaucrat in the alpha quadrant might have been stuck up with their preconceptions, but on voyager by then everyone considered the doctor a person.
And in any case the CMO can’t demote anyone.
The quarterly evaluation process as seen on the TNG episode Lower Decks (Not the cartoon) goes as follows.
1.Department heads write evaluations and recommendation about the crew daily, and send them to the first officer.
2. Every 3 months the first officer and the ships Counselor sum up the department head evaluations, and passes on those recommendations for promotions and transfers, and their interpretation, and their recommendations to the captain.
3. The Captain considers the recommendations or simply rubber stamps the 2000 page pdf because he trusts Riker, and sends the evaluations and promotion recommendations to Starfleet command.
4. Starfleet command makes sure nothing hiinky is going on, then approves the recommendations for promotion or transfer, and then sends it back to Picard.
5. Picard passes the paperwork back to Riker who informs everyone about their change of circumstances or lack of change of circumstances.
The Ships Counselor is an important part of the process. The XO says if he thinks a crewman is proficient enough to be promoted to a new job, and the Counselor figures out if the crewman is all there enough to handle the increased stress of a new job without overloading a phaser in the mess.
If Kes was the CMO, and there was as yet still not a ships Counselor on Chakotay's Voyager, she would be a fine substitute for the Counselor, who's job it is to make sure that Tuvok, Captain Chakotays XO, doesn't promote of demote or transfer crewmen to where they shouldn't be promoted, demoted, or transfered, for the sake of their own mental health.
If the Doctor is sentient he is a slave.
If the Doctor is a slave and his friends are treating him like a free man, then they are subversive criminals awarding an Ai liberties he is forbidden to hold because the default setting for all AI is "kill all humans".
Think of the antebellum south. The law of the land is shitty, but its the law of the land, and if you try to do the right thing, against the law, there's a possibility you might be whipped to death.
