Maybe it's not easy to be kind to people with whom you disagree, but it's possible. Case in point: the former neo-Nazis who help their former comrades leave hate groups behind.
That's just one example psychologist Jamil Zaki provides in his book The War for Kindness: Building Empathy in a Fractured World. Building empathy? Yes, Zaki points out that empathy is not fixed at birth, it's learned. The author lays out the details.
Bonus feature: even without the book, you can take the #kindnesschallenge. Posts begin July 8, 2019.