Hatred is based upon fear, people fear what they don’t understand. Racism or bigotry, intolerance is often based around not knowing enough about a certain group of people.
In this video, a black man becomes friends with a high ranking member of the KKK who had gone to jail for shooting black men, while also being a police officer.
He was raised to believe that his race is superior, the races should not mix, and he said that it was cemented in his mind, perhaps unwilling to go against the message he preached to so many people for so many years, even if he now saw flaws in those ideas.
This is called cognitive dissonance, when you have been raised with a particular world view for many years, it becomes a part of the structure of your brain, and anything that challenges that long held view is uncomfortable to deal with, causes anxiety, stress.
There are various things that can cause cognitive dissonance such as religion, politics, sexual or social stigmas, opinions about certain lifestyles that aren’t your own.
It can become very divisive, these different ideologies, an us and them mentality, and the more one side pushes on the other, the more they push back, defensively.
So who is “right” in these debates? The answer would be they are both right, from their own point of view. It isn’t black or white, and even if it was, metaphorically or literally, in terms of right or wrong, good and evil, there isn’t one right answer.

From a Zen perspective everything is everything, and everyone is right, if they believe they are right, because that is their reality, and their belief, both existing in the whole.
There are some solid facts, some potentially objectively real scientific realities like life and death, however even that is a subject you could debate, and the best approach to have in life is to constantly question yourself, as well as everyone else around you, because people have been shown to be “wrong” many, times before, even everyone in a society.