Here's what I think, and this is nearly 100% conjecture, because I refuse to read Vice, and have for a long time. I think the mystique is something like this: "The world is a joke. Only we get the punchline, but we're going to let you in on it one article at a time."
After reading Vice, people come away with a sense that they understand why the world is as dysfunctional as it is. People like simple answers, and people like knowing things that other people don't know. Vice wraps both of those in a tiny little package with a ironic bow on top, all couched in a language that is meant to offend the easily offenable. My guess is that Vice's readership is mainly formerly sheltered college freshmen whose eyes are just being opened to the world, and who don't really like what they see.