Here's why white conservatives are not entitled to quote MLK against the Black community: MLK never agreed with any of the white conservatives who quote him against the Black community; when he walked this earth white conservatives hated MLK and did all they could to bring his nonviolent movement to a halt, because white conservatives never actually accepted that Jim Crow was wrong and because they never accepted that Black resistance to Jim Crow was in any way legitimate; and when he was murdered by a right-wing white man- possibly in conspiracy with others- most white conservatives were actually relieved.

And just as is the case with BLM, white conservatives almost universally accused MLK of being a "Communist"- a term that was never really part of political reality in this country and a party which was totally irrelevant in the 1950s/60s black freedom struggle- simply because he denounced the Vietnam War for what it was, an immoral, unwinnable and essentially imperialist endeavor.

BTW, there is nothing "un-American" in using words like "anti-imperialist", since this country was born of a violent anti-colonial revolt against the British Empire.