As Dunham understands, just because you've "mined" your life for material doesn't mean it can't function as fiction and also work in many other registers than "This is what life is like for me" (which is, I think, a very constraining one). And as tachyonEvan said, many of her critics seem to assume otherwise.
"Hipster" seems like it started in its current sense as a stylistic designation (ironic and/or cheap-retro clothing), but to me it describes a person who engages culture in a superficial way in order to create an impression of superiority, especially in breadth of knowledge, obscurity or idiosyncrasy of taste, or integrity-via-consumption (esp. beer, clothes, music, film, kitsch).
I'm not sure I understand why especially
those, if it's about the more general ways of engaging with culture as you say? I've met arrogant know-it-alls who pose and pretend to know much more than they actually do from pretty much every age and background, regardless of the topic of conversation (sports, wine, history, pop culture, socialites who go to the opera or an art opening to be seen rather than from an earnest desire to see the art, the economy/business). I don't see how an existing term that can be used to describe only some who fit this people as some kind of subset of the culture, and I'm one of those who've gotten tired of the word because it's so vague and overused, for some describing almost anything they don't like as long that bears some resemblance to perceived pretense (but usually only thrown around in reference to all manner of young city-dwellers). Anyway, here's something else to move to the thread on "hipsters" as it's really about that discussion of the label more than about Tiny Furniture