Ryan is (finally) right. "Hipster" as a pejorative is used nearly exclusively by other hipsters, or expired hipsters, who would be hard pressed to explain how the same word didn't apply to them.
You say it = you are it. And who the F cares.
To me, a bunch of twentysomething idiots hating on another bunch of slightly younger twentysomething idiots for being 'hipsters' is mighty funny. But then, what am I but a 39 year old expired hipster? I'm sure all the 43 year old expired hipsters used to look down their noses at me when we were all twentysomething idiots. Now they look with envy at my slightly less gray hair and slightly less flabby gut.