Hatred of sinners
Hatred of our fellow sinners is a great sin--a capital sin that kills our relationship with God.
It is not hard to see sins in others. It's not brain surgery or rocket science. We can sense the difference between good and evil, and we can know with certitude that there have been and are real evildoers in the world.
Their sins are evil. We must avoid the second sin in our hearts of responding to their evildoing with our own evildoing. We must condemn their sins without giving sin a place to dwell in our hearts.
If we hate them, we become like them.
God has not set us up as the judges of who is and who is not beyond His mercy. Our job is not to condemn His children--in AA, they call this "taking someone else's inventory-- but to love them, not because of their evildoing but because they have God as their Father, Jesus as their Savior, and the Holy Spirit as the fountain of life within them.