I think that given the target of Fitzgerald's work, it seems to be a critique of modern bourgeois values that emerged in the 1920s. Through his characters, Fitzgerald seems to be indicting the social culture that values money over people, and status over individual dignity. The fact that Gatsby believes that the more money he possesses, the more wealth he can display, the greater the chance he wins Daisy would prove this. Gatsby, himself, is a believer that happiness is directly related to wealth acquisition. While it might not be an expressed view of capitalism, it is certainly implicit in its desire to preserve self-interest aims. I suppose that Nick's repudiation of the lifestyle that he was once a part might be a statement of resistance against a way of living that is predicated so much in the present and with the objectification of ideas and emotions.
The novel The Great Gatsby is a repudiation, denunciation, and condemnation of bourgeois values. Tom is the predominant bourgeois figure in the novel. Gatsby is a corruption of the American Dream, as is his gangster business partner/friend, but they do not necessarily represent bourgeois values. Tom is the status quo. The others are unusual in American society. Bootleggers do not represent the American norm, and they do not care about respectability.
Tom, on the other hand, is typically bourgeois. He feels superior to those without money, thinks his way is the best way, is ignorant and bigoted, thinks males and females should be held to different standards in terms of extramarital relations, and flaunts his money every chance he gets. He is the stereotypical bourgeois businessman. He cares about respectability and what others think of him. Gatsby does not.
Gatsby's dream isn't about money. It's about Daisy. Gatsby raises himself up to a high level of wealth so that he has a chance to win Daisy back. It's not about money for Gatsby. It's about money for Tom.
And Tom comes off badly in the novel. He is revealed to be all of what I've mentioned above.
The novel is an indictment of the bourgeois, and that is most evident in the character of Tom.
When you say "Gatsby" I'm not sure if you mean the character or the book.
I would say that the book definitely resists materialism and the desire to get ahead. I think it is saying that Jay Gatsby's dream is really empty.
If you are talking about the character of Jay Gatsby, I think he is affirming materialistic values. He wants to gain wealth because he wants the things (Daisy) that wealth can bring him. I would say that he sort of resists middle class values because he is willing to try to get a married woman away from her husband. I think you can also say he resists bourgeois values because he does not care if he makes his money illegally -- all he cares about is being rich so he can get Daisy.