The right attitude to hold toward any fellow human being is loving-kindness. That attitude is not only commanded by sacred scriptures but validated by human experience throughout history, however hard it is to achieve in our behavior.
This principle applies even to the young man in Aurora, Colorado, who killed 12 and wounded 58 terrified people in a movie theater with assault weapons. Even to him.
Although he shattered the highest law of love himself, causing horror, agony and grief worldwide, the Law of Love still applies to him. He must be loved, even as he is aptly prosecuted and judged. He must be pitied for whatever affliction warped his heart and mind away from recognizing and living the intrinsic principle of humanity, which is to love one another.
His horrible crime proceeds from lovelessness.
Not knowing love, not feeling loved himself (we must assume), he aimed to spread his misery to others, massively. With an act of anguish, a cry of despair, he meant to drown others in the despondency that had engulfed him, supposing that nothing could make him feel worse than he already felt, and misery loves company.