(Tom Gauld/You're All Just Jealous of My Jetpack)
The critical difference is the amount of damage that a professional can do to his clients. A depraved lawyer can send innocent people to prison and an immoral journalist can spread destructive lies.
We librarians can be fiendish, usually as a result of the dark rituals required in library school. But there's a reason why there are few villainous librarians in comics.
But no mad scientists (formerly called 'mad doctors')?
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