What are the moral values represented in The Great Gatsby, and what is F. Scott Fitzgerald's opinion of those?

As the previous answerer has already mentioned, this novel is a scathing criticism of the moral recklessness of the American upper class. It shows the irresponsibility of American capitalism and privilege. It does, however, present a moral alternative to this life, a set of values that might be better. Nick hints at it in the beginning of the novel. He says that  "Gatsby turned out alright. It was what preyed on Gatsby...that temporarily closed out...

As the previous answerer has already mentioned, this novel is a scathing criticism of the moral recklessness of the American upper class. It shows the irresponsibility of American capitalism and privilege. It does, however, present a moral alternative to this life, a set of values that might be better. Nick hints at it in the beginning of the novel. He says that  "Gatsby turned out alright. It was what preyed on Gatsby...that temporarily closed out my interest in the... elations of men."

Nick finds the majority of the characters morally disgusting. Tom cheats on his wife and displays racist tendencies. Daisy obsesses over wealth, has an affair with Gatsby, and lets Gatsby take responsibility for what she does to Myrtle. Jordan is frivolous and cheats at golf. By the end of the novel Nick can hardly stand any of it, despite his mentioned tendency to listen without judging.

The only one he forgives is Gatsby. I believe this is because the core problem he sees in the others is their selfish obsession with wealth, pleasure, and excitement. They are taken in by the commercialist vision of money and easy happiness. Gatsby is no better than anyone else in this sense. He engages in criminal activity to gain wealth, but he does it all because of a deeply romantic love for Daisy. He is not selfish or greedy; he is in love. This is what Nick means by the forces that prey on Gatsby. He is pulled into the mess because of his feelings for Daisy. He only falls prey to these forces as a a tactic for winning her affection.

All of this suggests that Fitzgerald was making the moral argument for a life that values love, relationships, and meaning over money, pleasure, and selfishness.