Within the setting of the 1930s, blacks--called Negroes at the time--were certainly marginalized, especially in some parts of the United States. Crooks is, therefore, made to leave in a little shed that leaned from the side of the barn. Of course, his alienation from the other men in the bunkhouse leaves Crooks bereft and despairing as evidenced when he negates the men's plans to have a farm by telling Candy it will never happen.
Because of his alienation, Crooks is very defensive, keeping his distance and requiring the same from others. For instance, when Lennie appears in the doorway, smiling to seem friendly, Crooks sharply repels him,
"You got no right to come in my room. This here's my room. Nobody got any right in here but me."
Yet, Crooks's loneliness overcomes him, and when he notices Lennie's "disarming smile" he invites Lennie to come in and talk to him. As they talk, Crooks explains that he is not from the South and his father owned a chicken ranch. He even played with white children, but his father disapproved. However, it is only now that he understands why.
"There wasn't another colored family for miles around. And now there ain't a colored man on this ranch an' there's jus' one family in Soledad....If I say something, why it's just a n-- sayin' it."
The proof of what Crooks tells Lennie comes when Curley's wife enters the barn later in the evening. Crooks tries to get her to leave, telling her also that she has no right to be there--"Now just get out, an' get out quick--because he fears being seen with a white woman. He threatens to ask the boss to tell her to stay out, but Curley's wife retorts,
"Listen, N---,....You know what I can do to you if you open your trap?....you keep your place, then,....I could get you strung up on a tree so easy it ain't even funny."
After this verbal encounter,
Crooks had reduced himself to nothing....Crooks sat perfectly still, his eyes averted, everything that might be hurt drawn in.
He puts on "layers of protection" against the prejudice expressed against him. But, after Curley's wife walks away, Candy tells him that she should not have spoken to Crooks as she has. But Crooks replies "dully,"
"It wasn't nothing...You guys comin' in an' settin' made me forget. What she says is true."
For a while, Crooks was the equal of the others; however, Curley's wife has reminded him of his marginalization. His social ostracism because of his color leaves Crooks reduced to a life of more loneliness than that of the other workers.