So I may be misinformed on this. But I read some stuff that claimed before his death, MLK had shifted focus to an emphasis on proletariat/bourgeois dynamics and that he was criticized within the black activist community for focusing too much on pro-union work instead of race activism.

I'm not American so I'm sure most here know alot more about him than me. Is this narrative of MLK becoming more Marxist in his later years and (allegedly) shifting focus from race to class incorrect?