I dunno - why do old audiophiles like such terrible music?
The point being, the question was doomed from the start. It takes a generalization (hipsters) and leads into a unfalsifiable claim of preference (prefer analog). This is covered in Philosophy 101.
The real answer is that they are hipsters because they prefer analog. Any discussion past this statement is just insulating, quite frankly, to the group of people this community needs to survive. Sure, a lot of young people will treat analog as a fad and move on, but such is life. Some will not, and they are the Audiogoners of the future. Nowadays, they will happily take that old tape deck off your hands. Also, as others have pointed out, the resulting reissues due to the popularity are a welcome relief to the incredibly high prices of some originals. This is a win win.
This is all coming from a 50 year old often referred to by my peers as a hipster - so take it for what its worth.