It even went further: in Romania, there was a popular movie in the 80s where the main plot is a high school student going to the math olympiad and his classmates cheering for him (with additional romantic threads of course).
A movie cheering for, or even trivializing anti-social behaviors would find it difficult to go past censorship (not to mention - to be conceived in the first place...)
It's for the same reason that you'd be hard-pressed to find a pre-1989 Central/Eastern European movie depicting any subcultures (like punks or hippies) sympathetically.