It was militant activists like Malcolm X who broadened the mainstream appeal of pacifists like MLK.
See “the radical flank effect”.
https://academic.oup.com/pnasnexus/article/1/3/pgac110/6633666
“There are many people who feel that it is useless to continue talking about peace and non-violence against a government whose only response is savage attacks on a defenseless and unarmed people.”
-Nelson Mandela