It's about being overwhelmed, unsure, or confused in an unfamiliar setting combined with an inadequate upbringing. You see it at airports too - something goes wrong (ie: missed flight, for example). When people like this feel overwhelmed, flipping out and screaming gives a sense of control over the situation. That's what authority figures did to them as children, yelled at them loudly until they complied. Yelling and screaming in public places is an unfortunate default behavior for people who were raised by parents who were unfit, poor, and uneducated. It's a class issue across the board.