King did not call for calm, in fact often the opposite. Here's a quote from him:
“Nonviolent direct action seeks to create such a crisis and foster such a tension that a community which has constantly refused to negotiate is forced to confront the issue. It seeks so to dramatize the issue that it can no longer be ignored. . . . I must confess that I am not afraid of the word ‘tension.’”
King was non-violent, but he did not avoid conflict. King regularly called on people to break laws because they were unjust. He specifically called for increasing tensions. And he was called an 'agitator'. He specifically chose not to condemn riots:
“But it is not enough for me to stand before you tonight and condemn riots. It would be morally irresponsible for me to do that without, at the same time, condemning the contingent, intolerable conditions that exist in our society. These conditions are the things that cause individuals to feel that they have no alternative than to engage in violent rebellions to get attention. And I must say tonight that a riot is the language of the unheard.”
And he famously objected to calls for calm and order:
“I have almost reached the regrettable conclusion that the Negro’s great stumbling block in his stride toward freedom is not the White Citizen’s Counciler or the Ku Klux Klanner, but the white moderate, who is more devoted to “order” than to justice; who prefers a negative peace which is the absence of tension to a positive peace which is the presence of justice”
Edit: Removed my judgement of the parent poster's understanding of King from the comment.