You are a liar.
The Serbs there were a constituent nation and the constitution granted to them the right to self-determination.
Educate yourself before you start lying here:
http://www.arhiv.sv.gov.yu/a100008g.htm
"Socialist Republic of Croatia is a national state of Croatian people, state of the Serb people in Croatia, and the state of nationalities residing therein."
.
.
.
Paragraph 3 "The Socialist Republic of Croatia is within the composition of the Socialist Federal Republic of Yugoslavia."
Article 3 of the SFRY constitution
"That the socialist republic is a state based on the sovereignty of the nations and on the rule of the working classes and all working people and the socialist self-management democratic immunity of working people and citizens and equal nations and nationalities."