The main principles of his ideal state are mutually different. On one side, he says about justice and equality while on the other hand, expounds communism that is to deprive the two classes from the private ownership and natural family life.
Further, the majority professional class is free of communism. It is clearly against the concept of justice and equality. So, his concepts of communism and justice are colliding with each other. Temporary marriages and nationalization of all the means of production are not natural and are against human nature. Under this theory, Plato opines that the soldiers and guardians cannot have a family and own private property to avoid corruption and to ensure justice for all.
However, how can we call these actions as justice when we are injustice to certain group of people?