I stayed over there for about one year just before the fighting would start. Yugoslavia was a beautiful country indeed.
Yugoslavia was an ethnically mixed state, with the exception of Slovenia. Serbia tried to keep its terriorially disparate Orthodox communities in one state, but was too weak to do so in the end. There was also a growing unwillingness of the rich northern countries to pay for the less developed southern countries (just like today in the EU).
After the economic failure of communism, there was also a crisis of idealism and people were trying to find meaning in their past religious traditions. Politicians inflamed the divisions to secure their power. Islamism had hardly anything to do with it.
first of all the region was Illyrian, then it was conquered by the Roman empire, and it was the border between the West and East Roman (Byzantine Empire), which was Christian. Then the pagan slavs migrated/invaded it in the 650-700, and the Byzantine Empire fought them back (there are still villages in Greece that have Slavic toponyms).
The byzantine empire started declining, and the slavs created the first Bulgarian empire (the Bullgars were Turkic nomadic tribes who mixed with the local Slavs, but they were not Islamisiced then and eventually converted to Christian Orthodox). The different slavic tribes started fighting with each other and created the many petty kindoms which formed the today's south slav ethnicities. And eventually the Ottomans conquered the whole place in 1400s until the 1900s, including the Albanians and eventually the Romanians in north East, and parts of Hungary in the north.
So.... there is 500 years of conflict against the ottomans, but really there is another 1000 years of medieval conflicts that you are completely ignoring.