English to Italian Social Sciences Social Science, Sociology, Ethics, etc. Saggio

Dal saggio di Mill "A few words on non-intervention". È un po' tutta la frase (quella che comincia con "The true standard", più che l'espressione in sé, a risultarmi oscura: a cosa/chi si fa riferimento qui con "their" e "they"? E che labirinto è quel passo che parte da "knowing as they do that it cannot"per arrivare a "for its observance"?

"The only moral laws for the relation between a civilised and a barbarous government, are the universal rules of morality between man and man.
The criticisms, therefore, which are so often made upon the conduct of the French in Algeria, or of the English in India, proceed, it would seem, mostly on a wrong principle.
The true standard by which to judge their proceedings never having been laid down, they escape such comment and censure as might really have an improving effect, while ** they are tried by a standard ** which can have no influence on those practically engaged in such transactions, knowing as they do that it cannot, and if it could, ought not to be observed, because no human being would be the better, and many much the worse, for its observance.
A civilised government cannot help having barbarous neighbours: when it has, it cannot always content itself with a defensive position, one of mere resistance to aggression."