It is illegal to try to criticise a court decision in a way that is designed to impede the justice system and/or to interfere with the independence of the judiciary.
I am not a lawyer but as far as I am aware it is illegal to say publicly for instance that a court decision was politically motivated. You might argue that it would undermine the justice system but this is 100% in lack of accountability territory.
You can say publicly that a court decision was politically motivated. What matters is how it is said and somewhat by whom (a member of the government might be held to higher standards).