Loving a rasha does not mean to condone his evil deeds. If you love his soul you'll do everything possible to prevent him from doing wrong.
There are two types of sin, sin between man and God and sin between man and man. Sin between man and God is harmful – to one's individual soul, to the collective soul of one's people, and to the cosmic soul – on a spiritual plane. Sin between man and man is harmful not only spiritually but physically as well.
The sages teach that that which is dangerous is more severe than that which is forbidden.
Our first concern, as a loving and caring individual and as a just society, is to take every measure to prevent the rasha from doing evil to his fellow man.
There are two forms of love, that which hides the iniquity of one's beloved and that which reveals it. Towards the rasha we must adopt the second form of love. That love is so sensitive to the soul of the rasha that it knows his intentions, and takes measures to prevent his doing wrong before he executes it.