I'm not even sure MLK ever explicitly considered himself a socialist.

Well then.

"I am much more socialistic in my economic theory than capitalistic." - Martin Luther King Jr.

"Today, capitalism has out-lived its usefulness." - Martin Luther King Jr.

"Call it democracy, or call it democratic socialism, but there must be a better distribution of wealth within this country." - Martin Luther King Jr.

"We must see now that the evils of racism, economic exploitation and militarism are all tied together." - Martin Luther King Jr.

"The evils of capitalism are as real as the evils of militarism and evils of racism." - Martin Luther King Jr.

"If America does not use her vast resources of wealth to end poverty and make it possible for all of God's children to have the basic necessities of life, she too will go to hell." - Martin Luther King Jr.

(from https://www.commondreams.org/views/2019/01/21/11-most-anti-capitalist-quotes-martin-luther-king-jr)

It says a lot about the education system wherever you come from that you never learned MLK was a socialist. He HATED capitalism! Hated it! Also, the scientist Albert Einstein was a prominent socialist who wrote a famous article, "Why socialism?" explaining in detail why he was a socialist. Einstein and MLK believed in the same anti-capitalist struggle. https://en.wikipedia.org/wiki/Why_Socialism%3F