Why did different races in the Balkan Peninsula carry out Ethnic Cleansing??

Different "races" DIDN'T. They are ALL white.

Different ethnic, religious and national groups did the "ethnic cleansing" killings. Catholic Croats supported by Germany and the United States actually killed the most (in spite of propaganda in the western press), THEN Christian Orthodox Serbs supported by Russia (considered the "bad guys" by the U.S.), Muslims in Bosnia, Albanian Muslims supported by the U.S. in Kosovo, Slovenians, etc.

They committed these crimes because of nationalism. In the old Yugoslavia, a communist country, all nationalities were supposed to be equal. When Yugoslavia broke down and capitalism started to return, the only allegiances people had left were ethnic, national and religious.

Their economy was in a shambles, their people were ALL suffering, and unscrupulous leaders (supported by foreigners who wanted to take over parts of the country) mobilized their groups to blame the others, leading to hate and killing.

Before the breakdown of Yugoslavia, Serbs and Croats, for instance, had the highest percentage of mixed marriages and integrated neighborhoods of any ethnic mix in the WORLD -- WAY more, for instance, than black and white marriages and neighborhood integration in the U.S.

So MANY of these killings were actually people who killed their own relatives and neighbors!

To ME, this is proof that however bad Tito's version of communism may have been, capitalism and nationalism can be far worse.

Because of growing feeling of nationalism, which is classification based on language.

finally some one got balls, thank you LEFTwing gun nut VCC AM!
btw, check out this documentary:
http://quicksilverscreen.com/watch?video=44766

Because they're fighting for control in Yugoslavia and there are a lot of races there in the Balkans like the Serbs, Croats, Bosnians, etc.

because they were indoctrinated into thinking that some people were less human than others. look at Islam... same God Same book - but they have been conditioned to think a Sunni is so different from a Shiia that they will blow up a mosque of children to get rid of them

What racial differences you have in mind?

Hatred, wrath, grudge-holding.

Google the Jasenovac concentration camp - this is your first step.