It has to do with a murderous ethnic cleansing campaign mounted by an organized crime syndicate masquerading as the government of Serbia, and the choices it's victims were presented with as to who would aid them in their fight for survival, and the consequences of those choices being interpreted through your spite colored glasses.
Ignorance is bliss, however, and as you have proven to prefer a world view formed by familiar prejudice rather than disconcerting knowledge, I leave you to stew in your impotent rage, secure in the knowledge that Washington has an ally in Sarajevo, while you foam at the mouth about statistically irrelevant portions of Bosnia's population.