It's deeper than that, though. Bateman's not supposed to be a normal yuppie. He's an inconceivably wealthy old-money creature. This is only hinted at--his father's power and wealth which are way beyond the generic white-boy finance-major assholes he hangs with--but it's a super-important hint to understanding the book.
Bateman is obsessed with "fitting in" and being a person but he has no idea what a person is. His descriptions of clothes and music (which are intentionally ridiculous, Ellis says) are his perception of the culture around him.
The people he hangs with aren't Bateman, he's a singular creature in this book, and he's trying to fit into an empty culture and the verbal diarrhea is his only way of grasping it. The old-money wealthy lifestyle doesn't work for him so he's trying the consumption-driven-asshole lifestyle because it's the closest thing he can find to what a person is, what a life is. The only other alternative is the life of the poor/homeless/prostitutes which utterly repulse him. When none of these options satisfy him, over time, you see the cracks and that's where the violence comes in. (Unlike in the movie, it's very obvious in the book that the violence is not real, it's just cartoonish nonsense.)
The point is he can't find an exit (see the final paragraph). Culture is all there is. Even the violent fantasies, being as inhuman as possible, don't let him escape from the soul-crushing drudgery of having to embrace society in one way or another.
American Psycho is not about "wealth makes you a dirtbag", it's "we all barely exist as individuals because we can only exist through society or as a reaction to society". The criticism of corporate/finance types is just part of it because of the era the book was written in. It's not the real point of the book.
The movie misses all of this, by the way, and just treats it as a black comedy, which is totally fine.