Generally the prosecution has unlimited discretion to put any and all evidence of “motive” in order to prove guilt, but the judge here slaps down a defendant from testifying as to his motive in order to prove innocence.
This is clearly grounds for appeal. Frankly after this scene, I can’t imagine any reasonable jury returning a guilty verdict. They just witnessed first hand what it means to be part of a kangaroo court. When a defendant is precluded from explaining his motive for his actions, then there is no justice.
Welcome to the Soviet Union.
The jurors BETTER return a guilty verdict, otherwise they’ll be sitting in the hot seat. /s