Why was non-violent action so effective in the civil rights movement?

The nonviolent protests of the 1950s and the 1960s were very successful for several reasons. For example, the Montgomery Bus Boycott showed that African-Americans were very determined to achieve their goals. They walked, biked, or carpooled for 381 days, regardless of the weather, until they got what they wanted. They took these actions in a peaceful manner, not destroying property or hurting people.
Another reason why the nonviolent method was successful was that it showed the rest of the country who was really being violent. When the police in Birmingham turned the fire hoses on the protesters and used dogs to attack them, it showed the brutal methods that law enforcement was using. When the police beat the marchers as they attempted to march from Selma to Montgomery, it also showed how violently the police were responding to the nonviolent protests. These actions were captured by the news media covering these events. The whole country was able to watch and see these events unfold. This helped sway public opinion in favor of the nonviolent protesters. This helped to pressure Congress to act and led to the passing of the Civil Rights Act of 1964 and the Voting Rights Act of 1965.
Another factor that supported the nonviolent protesters was that those who were against integration went after black churches and killed black children. People were horrified when the 16th Street Baptist Church was bombed and young, black children were killed.
The constant use of nonviolent protests helped to sway public opinion and some lawmakers to take actions to deal with the civil rights’ injustices facing our country.
http://www.pbs.org/independentlens/februaryone/civilrights.html

https://www.voanews.com/usa/non-violence-was-key-civil-rights-movement