I honestly think hipsters eat with their assholes because they consume everything wrong.
There's no ironic appreciation of things we love, even of things that are in fact ridiculous, which a hipster might take and own and show the world the humor in it.
The difference being that a nerd would wear a D&D shirt because he loves D&D while a hipster would wear a D&D shirt because it's ridiculous that he is wearing a D&D shirt.
The thing about hipsters is that they take very seriously trying to make themselves look like they don't take themselves seriously.
The 'Hipster Nerds' like stuff because they hate it. It's like they ironically like it.