Why does Lennie go to Crooks' room?

Lennie doesn't understand the unwritten code of racial segregation. He appears in Crooks' doorway while checking on his pup in the barn. Crooks tells Lennie to go away, but the simple big man cannot understand that he isn't wanted. Crooks at last relents and allows Lennie to sit with him and talk. Lennie tells Crooks "about the rabbits" and Crooks vents about his mistreatment as an African-American.