It's an ideal in that people should be working towards taking control of the state apparatus and making it so. The class struggle will always make it impossible to reach, but it can always be pushed to be better.
There is no such thing as "blind" justice. What they mean with "blind justice" isn't justice at all, but rather a blind application of and obedience to law - which liberalism have always (and utterly falsely) conflated with "justice."