I'm not from Zagreb, but Dinamo has a lot of history and tradition. Plus some of our posters actually live there and have supported the club their entire lives. It is unrealistic to expect someone in that situation to cheer for Barca and not be labeled a "true cule" (whatever that means).
Dynamo Moscow, Bucharest, Minsk, Kiev, Zagreb, Tbilisi, Berlin are all related to the Communist Ministries of Interior that were known to use oppression against the people with their inhuman secret police and militias, teams are Blue-White similar to Police Uniforms except for Bucharest who is red and Berlin who were using redcurrant and there are also teams named like this in Africa where the Soviets wanted to spread their sphere of influence during their existence. Soviet teams founded in the 20's and the rest around 1945 when the chaos started to implement in the Eastern Bloc.
Same thing goes for the CSKA's ( and derivate names like Steaua ) who were the Soviet Army teams and Ministry of "Defense'' ( defending peoples asses from freedom ), the only way a team like that had value was because it was taken care by some Kim Jong-Un type leaders leaving other teams with no chance to compete.
Big tradition of killing people and torturing them and their families