Ahh..
I do not work in a psych unit, however, I work in a related environment. A long term care nursing home.
I cannot say with mathematical precision that there is not any actively malign or dehumanizing thought processes in the minds of the care givers. Depending on the nature of the patient, that could very well happen; biases against people happen for any number of reasons, and only in an idealized, robotic world would that never occur.
That horrible truth in mind, the flipside is also true; you will have caregivers that disagree with the assessments of their superiors for a wide assortment of reasons. Chief and principle among which, is that care givers are "with that patient" and with that patient "every day, all day." Being able to predict the patterns of behavior of a patient is necessary to successfully anticipating the needs of that patient (whatever they might be), and depending on the nature of that prediction, and lead to some odd patterns that are self-reinforcing, and can lead to seemingly mechanized care-- which while tailored for a specific patient, and their specific needs, looks for all the world like the patient is being treated like a thing rather than a person.
EG-- caregivers will notice some patterns-- say-- Patient frequently urinates themselves when certain conditions are met (or not met, as is usually the case here.) In order to avoid the patient being publicly incontinent, a bladder schedule will be started, that records times of day, and activities that occur, in order to find markers or factors that may be at play in the recurring incontinence. The results of that research will then dictate the care that the patient needs to avoid being publicly incontinent, even if that kind of care seems dehumanizing. (EG, "Ok Mrs Johnson, it's just after dinner, time to go use the bathroom."-- It makes it look like you are toileting Mrs Johnson like she is a kept pet, rather than anticipating that Mrs Johnson typically consumes 36oz of tea at dinner, and that her kidneys go into overtime, and she does not like leaving her bridge game to go potty, and routinely misjudges how long she can go without her bladder giving her the finger. The goal is to mitigate her disruption of things she does enjoy doing-- like her bridge game-- while also mitigating the causal factors that lead to her incontinence-- and, more than likely, also doing so while acknowledging that Mrs Johnson has mild dementia, and cannot stick with a routine on her own.)
Similar things happen in psych wards. Patterns in patient care come to light, and patient care plans are amended to accommodate that. Likewise, there are commonalities between patients, and their needs, such that generalized classes of care can be identified, and staff better trained toward that set of larger goals.
This leads to unfortunate circumstances where staff is told "This person has bipolar 1 disorder, and has violent outbursts." when that is untrue. (Vindictive parent, et al.) and so, they enact safeguards against that patient harming either themselves or others (such as restriction of allowed items in room, visiting schedules, et al.)
The problem should self-address, as "predicted pattern of behavior does not happen", forcing re-evaluation of care, to ensure that the patient is receiving the proper care. That re-evaluation process requires all kinds of sign-off by delegated authorities; direct care givers are the bottom rung of the totem pole (and for good reason), and so cannot just elect to change the planned care willy nilly. They have to report their findings, and advocate for changes in patient care, and that process is slow and methodical. (a necessary outcome of the litigious nature of modern society, and the like.)
That is not a good consolation to family members who know the patient, but lack sufficient medical credentials to make a legal determination, who see their family member receiving inappropriate care for their needs-- especially those that might take this personally-- QED.
The reasons why this evolving change in careplan is so glacially slow, and requires considerable data collection to get moving, is because there are families who are in absolute denial about patients and their needs, as well as families that are vindictive toward the patient, and try to impose unnecessary restrictions and aggressive care on patients that do not require it, and so, should not receive it. The facility has to be able to confront an accuser, either way, in court and say "Based on the information provided to us by a higher ranking medical professional, we conducted our caregiving in accordance with proper process." because anything less than that is just asking to be sued and fined out of existence, and then nobody will be getting care.
If Mrs Johnson really is incapable of moderating her tea drinking before her nightly bridge game, and really is incapable of pre-emptively deciding to toilet herself to avoid causing herself daily embarrassment at her bridge game (and likewise, also causing her fellow players to not want to play with her, causing social isolation, and other maladies) then the imposition of a toileting schedule can greatly improve her overall quality of life, even if it comes off as being mechanistic, and dehumanizing.
Similar unfortunate realities are also true of psych ward patients.