"Full citizen" is a philosophical abstraction romanticized in one of my favorite movies, Starship Troopers. But for practical purposes it's a vague legal status. (The right to vote in elections is diminished by the common choice not to bother. The obligation to pay taxes is clouded by the numbing complexity of the code. Many voters have to be driven to the polls, and many taxpayers have to be threatened by the IRS.) In reality specific exchanges between any individual and his or her surrounding society are what count, and these show an endless gradient of "citizenship" and variations in its salient meaning for different people.
In the nuthouse people know the ultimate implications and consequences of marginal and unacceptable behavior as no one in normal society can. It’s what institutional people deal in, every hour of every day. And it happens to be what defines city/civilization or absence of city/civilization, too. Without clear behavioral margins and consequences there is jungle, not society.
A civilized society needs security, which generally comes from soldiers or police. Artisans, merchants, intellectuals, etc., do not, in their professional capacities, protect anyone from violent crime and predation. They can even begin to feel that there isn’t really any violent crime or predation, if their soldiers and police are very successful. After such great success has continued for a while, the nuthouse gets established to support a theory that there may soon be no need for soldiers and police. But very quickly, people not in the nuthouse forget this rather sophisticated purpose.
The imperative to “treat mental illness” is so obvious to those who don’t actually do it themselves. But try to sell a policy to “disable all bad people neurologically” and there will be considerable outcry about atrocity and constitutional rights.
In the nuthouse there is constant and unrelenting propaganda about mental illness because the all-too-apparent truth has to be drowned out. Psychiatric “cures” are atrocities, especially when they are forced on unwilling “patients”. But everyone in a state institution has a strong vested interest in maintaining and supporting the myth – and they really do know it’s a myth – that murderers, sex offenders and other violent criminals were not culpable for their behavior because their brains were diseased in some way that prevented them from choosing to behave better.
Every culture stands on its essential mythology. People who participate in the environment and operations of locked, maximum-security state institutions for psychotic killers and perverts have unassailable claims to full citizenship, precisely because they work hardest to create our essential mythology.