Sure, but they're fully aware of what they're doing, so that mental illness in no way excuses them.

Anyone who kills, tortures, or rapes is mentally ill on some level, but that doesn't qualify for an "insanity defense" unless their mental illness meets certain criteria, e.g. being incapable of understanding the consequences of their actions.

Similar situation with a pedophile: sure, he must be mentally ill on some level, but he's aware of his actions and deserves to be executed as far as I'm concerned.

And quite frankly, if someone is so ill that they're hardwired for an uncontrollable urge to molest children, then that's an equally dambing proof that they have no right existing in a civilized society.