He may or may not have been a commie, but one of his finance advisors definitely was a commie. One of the reasons Hoover started massive surveillance of King was his refusal to get rid of the commie when the FBI brought the proof to him.
Whatever he’s called, King was at least a socialist, and definitely anti-capitalist/free market. The greatirony, of course, is that he, who claimed the moral high ground for what he proclaimed as freedom, aligned himself with those who regarded humankind as things, animals, or machines.