They also need to be conversant on the data. Someone mentioned Heather MacDonald below. I cannot reccommend her work highly enough. In print and in person, she is able to quote voluminous statistics and research that dismantles the lies that BLM spreads. Buy her books, The War on Cops, The Diversity Delusion, along with several articles on the absurd notion perpetuated by BLM that cops are targeting blacks. Commit some of the most striking statistics to memory so that you may use them when you encounter good faith actor who expresses support for BLM, but seems to be someone with an open mind. Use them when you encounter a bad faith, closed-minded person, as well. It's about the other people who are watching. When one person is calmly stating facts and giving real life examples and the other person is using slurs and spitting fury, whom do you think will impress normal people observing it and who will not?