I'm not certain your definition of "art fag" and her definition match. I don't think she includes the Engels-reading baristas in that category - that's why she listed them explicitly as "not working class". Rather, I think she's referring to artists who basically give themselves up for art, delving into really esoteric tastes and edgy artwork.
To use a couple pop-culture examples that you may or may not be familiar with: none of the characters in Rent are art fags. Isaac Mendez from Heroes may be, but we don't know much of his history before he became a junkie or what he does besides paint the future. The characters from Scott Westerfield's novel "The End Days" are, as are the somewhat-caricatured characters in Terry Pratchett's "Soul Music".
To use a couple pop-culture examples that you may or may not be familiar with: none of the characters in Rent are art fags. Isaac Mendez from Heroes may be, but we don't know much of his history before he became a junkie or what he does besides paint the future. The characters from Scott Westerfield's novel "The End Days" are, as are the somewhat-caricatured characters in Terry Pratchett's "Soul Music".