No, we have these rights because people exercised collective power in an organized and strategic manner. Including, yes, disruptive acts of protest which if you had asked instead of trying to shift the goal posts to, you would find that I support.
The isolated cases of lone wolf killings were not frequent enough to have any real effect but what effect it did have was to cause fear and division among the people we need to organize, and to give rhetorical weapons to the powers that be.