Does Nick Carraway continue to be an objective narrator? Find evidence that he does or does not remain objective

Although Nick says he is only honest person he has ever
met, he is not objective.

Reason #1: He
chooses sides.  He aligns himself with Gatsby, a known gangster.  He
arranges an affair at his own bungalow between Gatsby and Daisy.  Nick hates Tom and
wants Gatsby to steal his girl.  Nick knows that Daisy is only fantasy to Gatsby, yet
Nick perpetuates Gatsby's fantasy life more than he tries to clarify or stop
it.

Reason #2: He fails to intervene or
become a moral agent in the novel. He knows Tom is having an affair with
Myrtle.  Does he try to stop it?  No, he attends their party and watches her get
slapped.  He knows Jordan and Gatsby are both dishonest; he associates with them
willingly.

Reason #3: He does not prevent
tragedy; he does not even reveal tragedy. Nick lets Gatsby get killed
without warning him in advance.  He lets Tom get away without punishment.  In the end,
two dead men cancel each other out, and Nick accepts this.  Nick does not tell anyone
any of this, not even Gatsby's father at the funeral.  He would rather have his father
think his son was one thing, when, in fact, he was quite the other.  Again, Nick
perpetuates Gatsby's fantasy more than he tries to clarify it.