People that think they know what they are talking about, enforcing those talking points and/or idea onto others, expecting all who listen to accept their words as truth, and sound like arrogant douches (or anything similar to the given definition). This person would be expected at a Starbucks as part of the stereotypical image of the kind of people one would see at a Starbucks.
Starbucks savant: We need to get radical. You're not radical enough. We need to be radical!
Person 2: For what?
Starbucks savant: Uh...
Person 2: You are such an idiot.