Help me understanding this line please!?

Nick caraway is an unreliable narrator in the novel "the great gatsby" for the fact that earlier in the novel nick stated that he was brought up in the world as someone who is non judgmental. Yet even after saying that he later goes on to judge Tom and his relationship with daisy. Also nick says " I'm one of the few honest people I know"... Wait a minute didn't nick prove to the reader that he lied about being a non-judgmental person in the beginning of the novel? This ultimately show his unreliability in the novel as a narrator