Hipsters are expressing a certain discomfort with 'modernity', and do so with an element of irony - they are reacting to a marketing-based society that traffics in images and artifice, not real stuff. Thus they like things that feel 'real', like film, vacuum tube amps, vinyl, paired down fixie bikes, craft beer and local produce, back alleys instead of suburban lawns. The lumber jack and thrift store looks are explicit responses to a world that puts a premium on image and logo.
They are young and immature kids who are dealing with big cultural and economic transitions, and they are doing an impressive job of creating a lifestyle that is a creative response to the suffocating world the previous generation left them. It is easy to make fun of them, but as I have said elsewhere they deserve our support and understanding.
They help keep film alive! And what dinosaur here has not suddenly felt more relevant when a young kid wants to see their ancient rangefinder?