Why does crooks call to candy jus fooling i wouldn't want to go place like that?

Crooks calls Candy's dream of owning a farm with George and Lennie "just fooling" because he believes that it is unlikely for them to achieve such a dream given their circumstances. Crooks, as a marginalized black man, has experienced discrimination and understands the harsh reality of how society works, especially for those on the margins like himself. So, he doubts Candy's dream because he has learned to be cautious about hoping for a better future.