Because, unfortunately, ignorance runs rampant in the world, and so antiquated prejudices, such as racism and sexism, still live on through some people. It's sad.

Perhaps it began with Darwin and his 'survival of the fittest' theory. We outwit, outlast, out-something else (Copyright Survivor 1990-something) by creating insecurity and thus culling our competition. Humans by their very nature are driven to compete, improve etc and when that takes place, alot of the time ruthlesness takes over and humans will under-cut each other in whatever way possible just so that they can get rid of those they perceive to be a threat to their own potential to succeed. Also necessity being the mother of invention has contributed in a major way to competiveness and thus discrimination - racism being one facet of discrimination as a grouped behaviour / attitude affecting humans. It'd be great if we could all just get along but due to individuality, difference, uniqueness, that'll never happen. There's no way we can like everyone or be liked by everyone and sometimes when we want to justify our negative feelings towards another person, we look for something in them that is different to us - and skin-colour or physical appearance are the biggest forms of discrimination followed closely by religious / belief discrimination. Also, when we're fearful of something or unfamiliar with it, we try to gain a sense of understanding / ownership / superiority over it and one way of doing that is to find and focus on a difference and then create a label against the person / group we have encountered and are too ignorant to simply accept as yet another group in the world.

Because it seems to be human nature to need to feel better than or superior to others...the same inclination exists among religions, whose proponents always feel that their particular belief is better than or superior to others. It makes people feel special.

Because humans evolved as hunter gatherers in small tribes. Anybody in the same tribe was probably a relative, and certainly a friend. Anybody in another tribe was certainly not a friend, probably an enemy, and should be feared and exploited if possible. The pattern can see be seen in tribes in the rainforests. When the tribal system broke up we still had the habit of dividing people into "people like me" who are friends, and "people not like me", who are unknown or enemies. The easiest way to do this is on the obvious marker of race. But people also do it on religion, language, sexuality...

I think that racism derives from the natural human desire for a ballance of good and evil. People who are more inclined to act upon this desire will usually pick an easy platform to stand on and the difference of color or culture is a easy pick. The proof is that some whites hate asians and like blacks or blacks hate latino and like whites and the list go's on and on. To end this we must quit trying to change the image of what people hate but rather change our own perception.

Pitifully we can not deal with racism as we all humans have allthe same rights we can not judge a book by it's cover as we can not judge a person by their skin tone