The scene of the bombing was most probably included in the movie to make the audience realize the nonfictional nature of the incident.
The bombing had been orchestrated by White Supremacists who wanted to inspire fear in the hearts of civil rights activists. When the incident was made into a movie, the actual scene was included to drive home the point that the incident really happened.
In conclusion, the makers wanted to make sure people knew the bombing was real.
Find out more on the Birmingham Church Bombing at https://brainly.com/question/2816590.