My copy of Grote ("gift of Jonas Gilman Clark" in pencil on reverse of the title page, later withdrawn from the Clark University Library) is the second edition, 1867, not the 1888 new edition, to which Nicholas White refers. So I cannot check the page numbers that he gives. But below are the three passages which are my best guess for not so Sachs-y criticisms of Plato.
When you read these passages, do you ask yourself: "How is it that an article on Plato gets published in a prestigious philosophical journal, which adds nothing to a criticism advanced 100 years earlier by a much more distinguished scholar?" (I would add: if one looks at Grote's criticisms in context, one sees that they form simply a part of several searching criticisms of Plato, very much worthy of our attention, as I shall perhaps show later.) Isn't there something deeply wrong with our discipline, that this can happen?
Now in regard to the definition here given by Plato of Justice, we may first remark that it is altogether peculiar to Plato; and that if we reason about Justice in the Platonic sense, we must take care not to affirm of it predicates which might be true in a more usual acceptation of the word. Next, that even adopting Plato's own meaning of Justice, it does not answer the purpose for which he produces it--viz.: to provide reply to the objections, and solution for the difficulties, which he had himself placed in the mouths of Glaukon and Adeimantus (126).
The ambiguous meaning of the word justice is known to Plato himself (as it is also to Aristotle). One professed purpose of the dialogue called the Republic is to remove such ambiguity. Apart from the many other differences of meaning (arising from dissentient sentiments of different men and different ages), there is one duplicity of meaning which Aristotle particularly dwells upon. In the stricter and narrower sense, justice comprehends only those obligations which each individual agent owes to others, and for the omission of which he becomes punishable as unjust--though the performance of them, under ordinary circumstances, carries little positive merit: in another and larger sense, justice comprehends these and a great deal more, becoming co-extensive with wise, virtuous, and meritorious character generally. The narrower sense is that which is in more common use; and it is that which Plato assumes provisionally when he puts forward the case of opponents in the speeches of Glaukon and Adeimantus. But when he comes to set forth his own explanation, and to draw up his own case, we see that he uses the term justice in its larger sense, as the condition of a mind perfectly well-balanced and well-regulated: as if a man could not be just, without being at the same time wise, courageous, and temperate. The just man described in the counter-pleadings of Glaukon and Adeimantus, would be a person like the Athenian Aristeides: the unjust man whom they contrast with him, would be one who maltreats, plunders, or deceives others, or usurps power over them. But the just man, when Sokrates replies to them and unfolds his own thesis, is made to include a great deal more...The just man, so described, becomes identical with the true philosopher: no man who is not a philosopher can be just. Aristeides would not at all correspond to the Platonic ideal of justice. He would be a stranger to the pleasure extolled by Plato as the exclusive privilege of the just and virtuous--the pleasure of contemplating universal Ideas and acquiring extended knowledge (129-131).
[Plato] professes to have satisfied the requirement of Glaukon, by proving that the just man is happy by reason of his justice--quand même--however he may be esteemed or dealt with either by Gods or men. But even if we grant the truth of his premisses, no such conclusion can be elicited from them. He appears to be successful only because he changes the terminology, and the state of the question. Assume it to be true, that the philosopher, whose pleasures are derived chiefly from the love of knowledge and of intellectual acquisitions, has a better chance of happiness than the ambitious or the money-loving man. This I believe to be true in the main, subject to many interfering causes--though the manner in which Plato here makes it out is much less satisfactory than the handling of the same point by Aristotle after him. But when the point is granted, nothing is proved about the just and the unjust man, except in a sense of those terms peculiar to Plato himself (147).For more on Aristides "the Just", see this dictionary entry and Plutarch's life. Thus Plutarch:
In all the vicissitudes of public affairs, the constancy he showed was admirable, not being elated with honours, and demeaning himself tranquilly and sedately in adversity; holding the opinion that he ought to offer himself to the service of his country without mercenary views and irrespectively of any reward, not only of riches, but even of glory itself. Hence it came, probably, that at the recital of these verses of Aeschylus in the theatre, relating to Amphiaraus-
"For not at seeming just, but being so
He aims; and from his depth of soil below
Harvests of wise and prudent counsels grow..."
--the eyes of all the spectators turned on Aristides, as if this virtue, in an especial manner, belonged to him.