Bolivians racist against other Bolivians? Doesn't make sense to me.

For a country with lots of different races, skin colours, accents and social statuses, there sure is a lot of racism!! Bolivia is essentially devided into two regions that are devided by the mountain lines. The south East of the country is one region and then the North West is another region. I the north you have all the cities like Oruro, Pando, La Paz ,Potosi and Cochabamba, then in the South East you have Santa Cruz, Beni, Chuquisaca and Tarija. The people in the south are known as Cambas and that is something that we are all very proud of and is taken as a compliment!The name given to the Northern people is not so much a compliment as a great insult. They are called Coilla and generally  when you call someone a Coilla it is because you are either mocking them or you are being racist. Coillas are the indigenous people that dont have any European roots. The word Camba comes from the verb Cambiar which in english means "to change", when the europeans first came to Bolivia they settled in the South East because it was flat, had good agricultural potential and it was close to the borders of Argentina, Brazil and Paraguay, the northern part was too cold and had nothing really that the europeans wanted. Because of the altitude and mountains the Europeans didnt settle there and so the wealth that they brought with them never made it to the north. Cambas became recognized as superiors and the  Coillas got the reputation as poor  filthy people. Even to this day there is extreme racism against the Coillas and it is disgusting.
When my family went to La Paz my host dad would make comments and my classmates were appalled that we even wanted to go to La Paz for Easter.  Then when they found out that I had no problem with the Coillas they actually tried to make me see why the Coillas are "disgusting people" I was apalled with their efforts and made that very clear.