Crooks initially reacts negatively to Lennie because he is used to being ostracized because of his race and doesn't want to get his hopes up about fitting in. However, he ultimately lets Lennie in because of his vulnerability and need for companionship, which is something he can relate to.
No one ever ;lts him in and he is completely isolated so is bitter. He has good reason to be mad but let's him in because Crooks is nicer and really wants company. He realises Lennie is no harm.
He's rude to him because he doesn't like people that are bigger than him "For a moment Crooks did not see him [Lennie], but on raising his eyes he stiffened and a scowl came on his face." Crooks stiffening shows that he feels a little threatened by Lennie's presence - he is becoming defensive and ready to react to any attack Lennie might start. The scowl on his face shows he is doesn't want Lennie there and is trying to ward him off by being uninviting. To me it also shows he doesn't want to be disturbed and just wants to be alone in his room, tending to his back and reading all his books, as this is what he is used to and has come to accept. This un-ordinary occurrence makes him suspicious as normally white men do not enter his room. "Crooks said sharply, 'You got no right to come in my room. This here's my room. Nobody got any right in here but me.'" This again shows he doesn't want Lennie there. Crooks shows distrust towards him.
Because Crooks has suffered in his past from racism and discrimination in America in the 1930's, and it has made him bitter and twisted. The only way that Crooks can feel better is to make someone else feel what he felt. He isn't neccessarily a bad person, he has just been badly mistreated in the past and wants to feel better.
well, it all starts when whomp rats invaded earth from planet tatoonie. then a war started between the gonk droids and the whomp rats. the whomps won so that is why lennie was let in
pangit ang answer
The boss is surprised and suspicious that why is George is answering Lennie's question. Boss thinks Lennie is not much of a talker.- KingOfAll
Surprised then tells him to get out but then doesn't care and tells Lennie to take a seat.
George is devastated and feels immense guilt for not being able to protect Lennie. The other ranch workers, particularly Slim and Carlson, react with shock and some understanding of George's decision to shoot Lennie. Curley reacts with anger and seeks revenge.
Curley thinks that Lennie is making fun of him through his silence. Lennie is very large and Curley is short. Curley is defensive about his height and dislikes Lennie's silence.
Slim is understanding and sympathetic, offering George support and reassurance. Carlson is more concerned with the inconvenience and suggests George should have shot Lennie himself to avoid further trouble.
In the case of rust anyway, metal oxides form
Crooks reacts the way he does due to the discrimination and isolation he experiences as a black man on the ranch. He is oppressed and marginalized because of his race, leading him to be defensive, bitter, and wary of others. His behavior is a result of the systemic racism and prejudice that he faces in society.