This may seem impossible to you, but the history actually started before Clinton took his oath of office.
The point is: Serbs and Croats lived next to each other since the end of the 15th century. There have ben no massacres or ethnic wars betwen them. As MikeUmovi observed, the Serbs were free, the Croats were serfs. Austria hired Serbs to fend off the Turks at the Austrian border. The Serbs were tax-exempt. Being of a different socal status, their political aspration and alliances sometimes differed from those of the Croatian peasant serfs, who were jealous and hateful of the Serbs for being better off.
Ante Starcevic netted this antagonism and turned it into a political "philosophy" of pure hate for his political party of Rights. To him Serbs were not even human, and his followers to this date couldn't agree more.
Referred to as the "Father of the [Croatian] NAtion," Starecevic defined Croat nationalism on racism, and his followers have carried that dogma from one generation to another until this this very day.
The only thing that is related to 1991 -- considering the background just outlined -- is the the extent and foricity of Serb refusal to live in a secessionist state of Croatia which considers a pure and unadultered biggot Ante Starcevic as the "Father of the Nation."
Your attempt to equalize nationalsts on both sides shows a well known phenomenon that liberary science and Google.com cannot provide understanding of an issue, alebit they can provide the data.
As long as Croatia honors Starcevics, Franks and Pavelics, it will be what it has been over 140 years -- a country defined on hate and racism, without an equal -- except for Albanians.
What is so understandable? And as for Serbian animosity towards Croats, it's understandable considering what happened in WWII. Who came first, the egg or the chicken?
Croatia declared independence from Yugoslavia and was willing to proceed with it by using military force against the political and military institutions of the SFRY. In response to Croatia's declaration of independence, the Republic of Serbian Krajina declared independence from Croatia and was willing to proceed with it by using military force against the political and military institutions of the Republic of Croatia.
You see, this attitude of the Republic of Croatia is exactly what caused the war in the first place and made a political solution almost impossible. At the same time the leadership in Zagreb was demanding certain rights for their nation and refusing to allow these same rights to the Serbian nation.