The guy's behavior is so aggressive, it reads like an actor overselling an idea ("act like it's too good to be true and that makes you really suspicious! Tell him his country is filthy and his clothes look like shit!"). His body language is exaggerated.

>> However, the script reveals the writer's very likely to jump to assholish ad hominem.

You nailed it on the head. Simple emotional experiences are easy to write and low-effort effective.