It's hard to be kind if you let hate in.
Discussion
What is the correct response to evil? Should we not hate evil?
We should hate sin but love sinners.
Think of mankind like a big extended family where every man is your cousin by way of Adam.
When they sin, you should feel bad for them as they are relatives. You should hate their sin, and yours, like God does.
Ultimately, you want your extended family to find Christ.