I've been surprised, at times, that others can interpret this personal decision about my own behavior and beliefs as some "social cudgel" that I am wielding against them. I guess it doesn't take much to leap from "oh, are you a vegetarian?" to "you must think eating meat is unethical," to "you must think I'm evil for eating this burger," to "annoying snobby vegetarians, always acting superior and rubbing it in your nose."
Anyway. That hipster buying his fair-trade coffee might not be doing it to insult you. It might be something he's read about, thought about, and decided he cares about. He might figure that mostly it's an empty gesture, but maybe it'll do some good. If you want to buy some other coffee, he might be totally OK with that. Of course, YMMV.
That said, I think the "socially-conscious hipster" is less likely to be vegetarian or vegan and more likely to buy "free range" eggs and eat "happy meat". The thing that makes them hipsters is their lack of commitment and their willingness to abandon the position once something more hip comes along.
Maybe we'd make more progress if we stopped denigrating people for trying to do what they can. It may not be enough, but at least some people are trying to do _something_. But when you put people down this way, it makes them less likely to do anything, because no one wants to be labeled as vacuous and superficial (AKA "hipster").