It seems to me that the heart is the organ of love alone.
The heart is either whole (loving) or broken (stone).
For some the wound is too deep.
What is a loss of faith but a heart broken by the representatives of God. Mistaking the representatives for God's self (the father).
Ask yourself : What experiences has this person had to make him the way he is? Has he received enough love as a child? Has her trust been broken?
"Whoever does not receive the kingdom of God as a little child will never enter it." Mark 10:15 (NRSV) (i.e. What you were like before your heart was broken.)
Lovers of humanity have whole hearts.
Those who hate and do evil have broken or wounded hearts.
God does not differentiate. (As a father will not.)
"Love your neighbor, because he is like you." Mark 12 :31. This alternate translation* tells us that our neighbor is like ourselves. (i.e. A product of his or her experiences.)
So understand the other and heal his wounds (with love).
Lovers of humanity are those who have experienced love.
Evil doers are those who may not have received enough love.
* Rabbi Melchior - World Parliament of Religions, Melbourne.
(Scripture quotations (marked NRSV) are taken from the New Revised Standard Version Bible, copyright 1989 by the Division of Christian Education of the National Council of the Churches of Christ in the U.S.A., and are used by permission. All rights reserved.)