In real life the extent to which and in what situations an insanity defence should be allowed is the subject of a fair bit of scientific and a philosophical debate. The viewpoint that it should never be allowed is not unheard of but in by no means common

In fiction however the view point that not sending crazy people to jail in unjust seems to be strangely common among any one with a connection to a crime or who works in law enforcement in any way. The reason for this is that it creates conflict.I mean if the main cast arrested a schizophrenic for murder and every one just shrugged and said “obviously not his fault, send him to the funny farm” that wouldn’t be very interesting if no one argued

This is also sometimes put in plots because trying to put a crazy person away might simply be part of someone's job and having a protagonist do something they don’t agree with just because it’s their job isn’t exactly sympathetic

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Examples:

Live Action TV

• in the Law And Order franchise they usually try to give some logical justification as to why their tying to prosecute a clearly insane suspect but for the most part the characters talk about why their doing it in terms of this. Like ADA Alex telling Olivia that it was some how wrong not to prosecute a mentally ill man for using an under age prostitute if they prosecuted all the sane men who used her, or Captain Cragen complaining about how sending a rapist murderer to an institution rather then jail because he’s retarded is unjust to his why of thinking

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