Why did Claude McKay chose to represent Harlem in the way he did?

Claude McKay lived in Harlem during several periods of his life, but he wrote about it while living in other places as well as in this area of Manhattan. In poetry, fiction, and nonfiction, he addressed contradictory aspects of a place with which, as a foreign-born and often foreign-resident man of African heritage, he experienced a highly complex relationship. He sought to depict the area honestly, including confronting racism and other problems.
McKay was originally from Jamaica, where he lived until age 20. He began writing and publishing poetry there. Upon moving to the United States, he enrolled in Tuskegee and then studied agriculture in a Kansas college before moving to New York, where he worked a wide variety of jobs and pursued a writing career.
In Harlem, McKay was immediately caught up in the African American cultural movement that became known as the Harlem Renaissance. McKay’s poetry in particular was well-suited to the radical re-evaluation of race, politics, and art that figured into the movement. While involved in racially-based cultural explorations, McKay also looked at social justice issues that concerned all working Americans. Becoming increasingly involved with left-wing political movements, McKay joined the editorial staff of The Liberator. Discouraged by the US political and racial climate, McKay decided to move overseas; he continued writing for socialist papers in England. Upon his return to New York in 1921, McKay published a book of poems called Harlem Shadows. This work was lavishly praised and cemented his reputation as the premier black poet of his generation.
Still dissatisfied, however, McKay began traveling again, this time to Moscow. There he met with prominent Communists and even gave speeches about racism at major congresses. His decision to continue living overseas rather than return to the United States was a major turning point. Living about 10 years in France and North Africa, he continued to write poetry and fiction. While much of it was set in those locales, he also wrote and published Home to Harlem during that time. The novel presents the character of Jake who, similar to McKay, cycles in and out of Harlem, feeling both deeply connected to and severely alienated from the area. Writing frankly about many negative aspects, including the underworld, McKay sought to depict it accurately but was sometimes criticized for showing black life in an exaggeratedly negative light.
When he finally came back to the United States in 1934, not only was the Harlem Renaissance well past its prime, but the whole country was sunk into the Great Depression. McKay had come to feel culturally, artistically, and spiritually disconnected from New York, and he endured deep financial troubles. Increasingly he examined Harlem by looking back to its glory days, and in 1940, he published the historical work Harlem: Negro Metropolis.