Judges should have some amount of biases. A cold, calculating, unbiased judge in a world where laws are written by fallible humans would be terrible.
Judges should be able to apply judgement, not be merely automatons that sentence according to only the exact letter of the law.
Laws are not perfect, we need human judges.
Finally, if we are to submit ourselves to judgement by others, I gives me some comfort to know that the being judging me is equally mortal and can be deposed if necessary, as they are flesh and blood like me.
