Unfortunately, in the real world there is such a thing as being too nice or too kind. To be kind is to be of like kind. An unearned, undeserved kindness that is not reciprocated invariably has negative consequences for both the giver and receiver.
The laws of causality and of equal and opposite reaction apply no less to matters of morality. Turning the other cheek is only a virtue if you had it coming to you. Justice demands commensurate treatment for both offender and victim. A kindness bestowed blindly and without consideration is an insult to kindness bringing injury to those attempting to be kind without just cause or good reason.
Anything of value carries with it a price which demands the compensation of acknowledging respecting and honoring it for the value that it is. Goodness is not created out of thin air but arises from knowing what good is, being able to recognise it when one sees it, rewarding its creators commensurate with their production of and allegiance to it.
Evil left to its own devices is self-destructive and self-annihilating and exists only by virtue of the good that is sacrificed to its cause. Religion, in the inculcating of its dogma of worshipping sacrifice, suffering and death through the emotional blackmail of its followers, offering the less innocent an alleged escape from personal responsibility, a trapdoor to self-loathing, rendering both unable to make a proper distinction between what is in fact good and evil, is one of the main causes of and contributors to the evil so prevalent in the world today.
Reason, in providing the species that inherited the potential to discover and use it the ability to distinguish good from evil and to understand why one should be preferred over the other, is the milk of human kindness.