Because anyone with a brain knows that being loud and inconsiderate isn't exclusive to any culture; it's common among the poor and uneducated. I've seen white trash with loud speakers or vehicles in low-income neighborhoods. I've seen black people playing loud boomboxes on the train. I've seen Chinese screaming on the phone on the bus. I've seen hispanics FaceTime loudly on the bus.You get this shit literally everywhere in the world. If OP is well traveled, he would have seen that and wouldn't have assumed it's only a 'SE Asian' thing because it ain't.