At the same time, labelling someone as mentally ill can be a form of exercising your power over another person and silencing the unusual.
This has been done over and over in history and is still present today.
For example, was being transgender still listed in the ICD (a list of all the possible diagnosis’) until 2018! Even though the facts show us that a transgender person - if she can express her gender as she wants to- has no greater risk of becoming mentally ill as a binary-cis person.
As society changed there were more and more protests against this external description as ill which led to a revision of this paragraph.
This shows us that these diagnosis’ are not only a mirror of the latest scientific insights but also a mirror of society and its latest values. And these are mainly influenced by those in power.
So, we should always look at diagnosis’ in the context of its time and check if they are really based on facts and not on opinions. Psychology is moving forward and getting rather objective criteria but a scientist can also be influenced by his values without himself even noticing and it is really hard to avoid this.
This is the reason why mentally ill people should always keep their basic rights like for example voting. Otherwise, a subjective diagnosis is just a too powerful weapon.