I glossed on the racial aspects and tended to treat them as incidental. When things like that appear in books meant for a certain period I just take that as a history lesson on the side rather than a message or theme. I suppose that the author is reflecting the attitudes of the time for us - in this case with some honesty I imagine.
I could be wrong of course. Based on your post issybird, I did some searching on the internet and came up with the following article on F Scott Fitzgerald and race. It's a bit brief, but it seems to suggest that there might have been a transition for the author in his views on race over the course of his works. In his early works, scorn was directed at different races from his pen, but in later novels the scorn is directed to racist characters instead. Or at least that's what I think the article is saying:
http://webdiary.com.au/cms/?q=node/1575