The obstacle of geography has been vanquished since the relatively recent technological advances in travel. This has bridged the gap between cultures, but these cultures have collided violently as opposed to harmoniously. As a result, we live in a country rife with intolerance. People are compelled to find differences in appearance and then write them off as oddities rather than viewing them as perfect opportunities to learn. Perhaps it is a mutual fear of change.
People are afraid of the unknown.
Often, this fear finds its release in the form of hatred. This mirrors the cause and effect of racism. When one culture is introduced to a new, unfamiliar society, their beliefs and values will inevitably clash. Rather than attempting to share their ideas and learn from each other, they shy away from one another, establishing defensive barriers. They look and behave differently from us, so they must be bad.